Misplaced Pages

#784215

129-397: In nutrition and food science , the term calorie and the symbol cal may refer to the large unit or to the small unit in different regions of the world . It is generally used in publications and package labels to express the energy value of foods in per serving or per weight, recommended dietary caloric intake , metabolic rates , etc. Some authors recommend the spelling Calorie and

258-919: A flagellum to assist in hunting for food, and some protozoa travel via infectious spores to act as parasites. Many protists are mixotrophic, having both phototrophic and heterotrophic characteristics. Mixotrophic protists will typically depend on one source of nutrients while using the other as a supplemental source or a temporary alternative when its primary source is unavailable. Prokaryotes , including bacteria and archaea , vary greatly in how they obtain nutrients across nutritional groups. Prokaryotes can only transport soluble compounds across their cell envelopes, but they can break down chemical components around them. Some lithotrophic prokaryotes are extremophiles that can survive in nutrient-deprived environments by breaking down inorganic matter. Phototrophic prokaryotes, such as cyanobacteria and Chloroflexia , can engage in photosynthesis to obtain energy from sunlight. This

387-577: A lower house based on population; and the Senate , an upper house based on equal representation for each state. Federalism provides substantial autonomy to the 50 states, while the country's political culture promotes liberty , equality , individualism , personal autonomy , and limited government . One of the world's most developed countries , the United States has had the largest nominal GDP since about 1890 and accounted for over 15% of

516-580: A " Special Relationship " with the United Kingdom and strong ties with Canada , Australia , New Zealand , the Philippines , Japan , South Korea , Israel , and several European Union countries ( France , Italy , Germany , Spain , and Poland ). The U.S. works closely with its NATO allies on military and national security issues, and with countries in the Americas through

645-542: A coordinated, continent-wide military effort. Finally, deteriorating relations between the British military establishment and the colonists, relations that were already less than positive, set the stage for further distrust and dislike of British troops. Following their victory in the French and Indian War, Britain began to assert greater control over local colonial affairs, resulting in colonial political resistance ; one of

774-534: A decentralized government that operated until 1789. After the British surrender at the siege of Yorktown in 1781 American sovereignty was internationally recognized by the Treaty of Paris (1783), through which the U.S. gained territory stretching west to the Mississippi River, north to present-day Canada, and south to Spanish Florida . The Northwest Ordinance (1787) established the precedent by which

903-407: A few prominent industrialists , largely by their formation of trusts and monopolies to prevent competition. Tycoons led the nation's expansion in the railroad , petroleum , and steel industries. The United States emerged as a pioneer of the automotive industry . These changes were accompanied by significant increases in economic inequality , slum conditions , and social unrest , creating

1032-638: A founding member of the World Bank , Organization of American States , NATO , and the United Nations , as well as a permanent member of the UN Security Council . The first documented use of the phrase "United States of America" is a letter from January 2, 1776. Stephen Moylan , a Continental Army aide to General George Washington , wrote to Joseph Reed , Washington's aide-de-camp , seeking to go "with full and ample powers from

1161-401: A higher requirement of energy in comparison to plants. The macronutrients essential to animal life are carbohydrates, amino acids , and fatty acids . All macronutrients except water are required by the body for energy, however, this is not their sole physiological function. The energy provided by macronutrients in food is measured in kilocalories, usually called Calories, where 1 Calorie is

1290-567: A nutrient deficiency. Early human nutrition consisted of foraging for nutrients, like other animals, but it diverged at the beginning of the Holocene with the Neolithic Revolution , in which humans developed agriculture to produce food. The Chemical Revolution in the 18th century allowed humans to study the nutrients in foods and develop more advanced methods of food preparation . Major advances in economics and technology during

1419-598: A period of heightened, overt racism following Reconstruction, a time often called the nadir of American race relations . A series of Supreme Court decisions, including Plessy v. Ferguson , emptied the Fourteenth and Fifteenth Amendments of their force, allowing Jim Crow laws in the South to remain unchecked, sundown towns in the Midwest, and segregation in communities across the country , which would be reinforced by

SECTION 10

#1732801813785

1548-488: A prominent leader in the early 1960s. The Great Society plan of President Lyndon Johnson 's administration resulted in groundbreaking and broad-reaching laws, policies and a constitutional amendment to counteract some of the worst effects of lingering institutional racism . The counterculture movement in the U.S. brought significant social changes, including the liberalization of attitudes toward recreational drug use and sexuality . It also encouraged open defiance of

1677-526: A sense of manifest destiny . The Missouri Compromise attempted to balance the desire of northern states to prevent the expansion of slavery into new territories with that of southern states to extend it, admitting Missouri as a slave state and Maine as a free state. It further prohibited slavery in all other lands of the Louisiana Purchase north of the 36°30′ parallel . As Americans expanded further into land inhabited by Native Americans,

1806-614: A sense of American identity as well. Men who otherwise never left their own colony now traveled across the continent to fight alongside men from decidedly different backgrounds but who were no less "American". British officers trained American officers for battle, most notably George Washington ; these officers would lend their skills and expertise to the colonists' cause during the American Revolutionary War to come. In addition, colonial legislatures and officials found it necessary to cooperate intensively in pursuit of

1935-481: A significant increase in human intake of fats and oils. Humans have developed advanced methods of food processing that prevent contamination of pathogenic microorganisms and simplify the production of food. These include drying, freezing, heating, milling, pressing, packaging, refrigeration, and irradiation. Most cultures add herbs and spices to foods before eating to add flavor, though most do not significantly affect nutrition. Other additives are also used to improve

2064-632: A status solidified after its involvement in World War I . After Japan 's attack on Pearl Harbor in December 1941, the U.S. entered World War II . Its aftermath left the U.S. and the Soviet Union as the world's two superpowers and led to the Cold War , during which both countries struggled for ideological dominance and international influence . Following the Soviet Union's collapse and

2193-566: A variety of foods. Cultivation of cereals and production of bread has made up a key component of human nutrition since the beginning of agriculture. Early humans hunted animals for meat, and modern humans domesticate animals to consume their meat and eggs. The development of animal husbandry has also allowed humans in some cultures to consume the milk of other animals and process it into foods such as cheese . Other foods eaten by humans include nuts, seeds, fruits, and vegetables. Access to domesticated animals as well as vegetable oils has caused

2322-401: A year). Juvenile correctional facilities are operated by local or state governments and serve as longer-term placements for any minor adjudicated as delinquent and ordered by a judge to be confined. As of January 2023, the United States has the sixth-highest per capita incarceration rate in the world—531 people per 100,000 inhabitants—and the largest prison and jail population in

2451-591: Is believed to be the first widespread culture in the Americas. Over time, indigenous North American cultures grew increasingly sophisticated, and some, such as the Mississippian culture , developed agriculture , architecture , and complex societies . In the post-archaic period , the Mississippian cultures were located in the midwestern , eastern , and southern regions, and the Algonquian in

2580-486: Is common among bacteria that form in mats atop geothermal springs. Phototrophic prokaryotes typically obtain carbon from assimilating carbon dioxide through the Calvin cycle . Some prokaryotes, such as Bdellovibrio and Ensifer , are predatory and feed on other single-celled organisms. Predatory prokaryotes seek out other organisms through chemotaxis or random collision, merge with the organism, degrade it, and absorb

2709-490: Is governed by nutrition. Migration patterns and seasonal breeding take place in conjunction with food availability, and courtship displays are used to display an animal's health. Animals develop positive and negative associations with foods that affect their health, and they can instinctively avoid foods that have caused toxic injury or nutritional imbalances through a conditioned food aversion . Some animals, such as rats, do not seek out new types of foods unless they have

SECTION 20

#1732801813785

2838-463: Is increasingly being superseded by the SI unit, the joule (J); and metric multiples thereof, such as the kilojoule (kJ). The lingering use in chemistry is largely due to the fact that the energy released by a reaction in aqueous solution , expressed in kilocalories per mole of reagent, is numerically close to the concentration of the reagent in moles per liter multiplied by the change in the temperature of

2967-498: Is known as the presidential system , in contrast to the parliamentary system , where the executive is part of the legislative body. Many countries around the world imitated this aspect of the 1789 Constitution of the United States , especially in the Americas. The Constitution is silent on political parties. However, they developed independently in the 18th century with the Federalist and Anti-Federalist parties. Since then,

3096-554: Is managed by humans through animal feed . Fodder and forage are provided to livestock. Specialized pet food has been manufactured since 1860, and subsequent research and development have addressed the nutritional needs of pets. Dog food and cat food in particular are heavily studied and typically include all essential nutrients for these animals. Cats are sensitive to some common nutrients, such as taurine , and require additional nutrients derived from meat. Large-breed puppies are susceptible to overnutrition, as small-breed dog food

3225-570: Is more energy dense than they can absorb. Most plants obtain nutrients through inorganic substances absorbed from the soil or the atmosphere. Carbon, hydrogen, oxygen, nitrogen, and sulfur are essential nutrients that make up organic material in a plant and allow enzymic processes. These are absorbed ions in the soil, such as bicarbonate , nitrate , ammonium , and sulfate , or they are absorbed as gases, such as carbon dioxide, water, oxygen gas, and sulfur dioxide . Phosphorus, boron, and silicon are used for esterification . They are obtained through

3354-438: Is now the United States experienced conflicts with Native Americans, they also engaged in trade, exchanging European tools for food and animal pelts. Relations ranged from close cooperation to warfare and massacres. The colonial authorities often pursued policies that forced Native Americans to adopt European lifestyles, including conversion to Christianity. Along the eastern seaboard, settlers trafficked African slaves through

3483-552: Is the federal agency charged with addressing most environmental-related issues . The idea of wilderness has shaped the management of public lands since 1964, with the Wilderness Act . The Endangered Species Act of 1973 provides a way to protect threatened and endangered species and their habitats. The United States Fish and Wildlife Service implements and enforces the Act. In 2024, the U.S. ranked 34th among 180 countries in

3612-403: Is the practice of eating food in a regulated way to decrease, maintain, or increase body weight , or to prevent and treat diseases such as diabetes and obesity . As weight loss depends on reducing caloric intake, different kinds of calorie-reduced diets have been shown to be generally effective. In other scientific contexts, the term "calorie" and the symbol "cal" almost always refers to

3741-1060: Is the same increment, a gradation of one percent of the interval between the melting point and the boiling point of water). The actual amount of energy required to accomplish this temperature increase depends on the atmospheric pressure and the starting temperature; different choices of these parameters have resulted in several different precise definitions of the unit. ≈  0.003 964   BTU ≈  1.162 × 10  kW⋅h ≈  2.611 × 10  eV ≈  0.003 985  BTU ≈ 1.168 × 10 kW⋅h ≈ 2.624 × 10 eV ≈  0.003 9671  BTU ≈ 1.1626 × 10 kW⋅h ≈ 2.6124 × 10 eV ≈  0.003 964  BTU ≈ 1.162 × 10 kW⋅h ≈ 2.610 × 10 eV ≈  0.003 971  BTU ≈ 1.164 × 10 kW⋅h ≈ 2.615 × 10 eV ≈  0.003 9683  BTU ≈ 1.1630 × 10 kW⋅h ≈ 2.6132 × 10 eV ≈  0.003 9683  BTU = 1.1630 × 10 kW⋅h ≈ 2.6132 × 10 eV The two definitions most common in older literature appear to be

3870-605: Is the simplest form of carbohydrate. Carbohydrates are broken down to produce glucose and short-chain fatty acids , and they are the most abundant nutrients for herbivorous land animals. Carbohydrates contain 4 calories per gram. Lipids provide animals with fats and oils. They are not soluble in water, and they can store energy for an extended period of time. They can be obtained from many different plant and animal sources. Most dietary lipids are triglycerides , composed of glycerol and fatty acids. Phospholipids and sterols are found in smaller amounts. An animal's body will reduce

3999-642: The 15 °C calorie and the thermochemical calorie . Until 1948, the latter was defined as 4.1833 international joules; the current standard of 4.184 J was chosen to have the new thermochemical calorie represent the same quantity of energy as before. In the United States , in a nutritional context, the "large" unit is used almost exclusively. It is generally written "calorie" with lowercase "c" and symbol "cal", even in government publications. The SI unit kilojoule (kJ) may be used instead, in legal or scientific contexts. Most American nutritionists prefer

Calorie - Misplaced Pages Continue

4128-603: The Allies of World War I , helping to turn the tide against the Central Powers . In 1920, a constitutional amendment granted nationwide women's suffrage . During the 1920s and '30s, radio for mass communication and the invention of early television transformed communications nationwide. The Wall Street Crash of 1929 triggered the Great Depression , which President Franklin D. Roosevelt responded to with

4257-553: The Atlantic slave trade . The original Thirteen Colonies that would later found the United States were administered as possessions of Great Britain , and had local governments with elections open to most white male property owners . The colonial population grew rapidly, eclipsing Native American populations; by the 1770s, the natural increase of the population was such that only a small minority of Americans had been born overseas. The colonies' distance from Britain allowed for

4386-549: The Environmental Performance Index . The country joined the Paris Agreement on climate change in 2016 and has many other environmental commitments. The United States is a federal republic of 50 states and a separate federal capital district, Washington, D.C. It also asserts sovereignty over five unincorporated territories and several uninhabited island possessions . The U.S. is

4515-500: The Federal Bureau of Investigation (FBI) and the U.S. Marshals Service have national jurisdiction and specialized duties, such as protecting civil rights , national security and enforcing U.S. federal courts ' rulings and federal laws. State courts conduct most civil and criminal trials, and federal courts handle designated crimes and appeals of state court decisions . There is no unified "criminal justice system" in

4644-576: The Great Depression and the Second World War. Due to its importance in human health, the study of nutrition has heavily emphasized human nutrition and agriculture, while ecology is a secondary concern. Nutrients are substances that provide energy and physical components to the organism, allowing it to survive, grow, and reproduce. Nutrients can be basic elements or complex macromolecules . Approximately 30 elements are found in organic matter , with nitrogen , carbon , and phosphorus being

4773-720: The Great Lakes , Mississippi River and Gulf of Mexico . British colonization of the East Coast began with the Virginia Colony (1607) and Plymouth Colony (1620). The Mayflower Compact and the Fundamental Orders of Connecticut established precedents for representative self-governance and constitutionalism that would develop throughout the American colonies. While European settlers in what

4902-719: The Great Lakes region and along the Eastern Seaboard , while the Hohokam culture and Ancestral Puebloans inhabited the southwest . Native population estimates of what is now the United States before the arrival of European immigrants range from around 500,000 to nearly 10 million. Christopher Columbus began exploring the Caribbean for Spain in 1492, leading to Spanish-speaking settlements and missions from Puerto Rico and Florida to New Mexico and California . France established its own settlements along

5031-596: The Midwest . At the same time, about one million French Canadians migrated from Quebec to New England . During the Great Migration , millions of African Americans left the rural South for urban areas in the North. Alaska was purchased from Russia in 1867. The Compromise of 1877 effectively ended Reconstruction and white supremacists took local control of Southern politics . African Americans endured

5160-688: The National Park Service and other agencies. About 28% of the country's land is publicly owned and federally managed, primarily in the Western States . Most of this land is protected , though some is leased for commercial use, and less than one percent is used for military purposes. Environmental issues in the United States include debates on non-renewable resources and nuclear energy , air and water pollution , biodiversity , logging and deforestation , and climate change . The U.S. Environmental Protection Agency (EPA)

5289-596: The New Deal , a series of sweeping programs and public works projects combined with financial reforms and regulations . All were intended to protect against future economic depressions. Initially neutral during World War II , the U.S. began supplying war materiel to the Allies of World War II in March 1941 and entered the war in December after the Empire of Japan 's attack on Pearl Harbor . The U.S. developed

Calorie - Misplaced Pages Continue

5418-778: The Organization of American States and the United States–Mexico–Canada Free Trade Agreement . In South America, Colombia is traditionally considered to be the closest ally of the United States. The U.S. exercises full international defense authority and responsibility for Micronesia , the Marshall Islands , and Palau through the Compact of Free Association . It has increasingly conducted strategic cooperation with India , but its ties with China have steadily deteriorated. Since 2014,

5547-648: The Pentium microprocessor in accordance with Moore's law , rechargeable lithium-ion batteries , the first gene therapy trial, and cloning either emerged in the U.S. or were improved upon there. The Human Genome Project was formally launched in 1990, while Nasdaq became the first stock market in the United States to trade online in 1998. In the Gulf War of 1991, an American-led international coalition of states expelled an Iraqi invasion force that had occupied neighboring Kuwait . The September 11 attacks on

5676-527: The SI derived unit of energy , the joule (J), or the kilojoule (kJ) for 1000 joules. The precise equivalence between calories and joules has varied over the years, but in thermochemistry and nutrition it is now generally assumed that one (small) calorie ( thermochemical calorie ) is equal to exactly 4.184 J, and therefore one kilocalorie (one large calorie) is 4184 J or 4.184 kJ. The term "calorie" comes from Latin calor  'heat'. It

5805-591: The Spanish–American War . (The Philippines was granted full independence from the U.S. on July 4, 1946, following World War II. Puerto Rico and Guam have remained U.S. territories.) American Samoa was acquired by the United States in 1900 after the Second Samoan Civil War . The U.S. Virgin Islands were purchased from Denmark in 1917. The United States entered World War I alongside

5934-623: The United States ( U.S. ) or America , is a country primarily located in North America . It is a federal union of 50 states and a federal capital district, Washington, D.C. The 48 contiguous states border Canada to the north and Mexico to the south, with the states of Alaska to the northwest and the archipelagic Hawaii in the Pacific Ocean . The United States also asserts sovereignty over five major island territories and various uninhabited islands . The country has

6063-440: The carbon cycle , sulfur cycle , nitrogen cycle , water cycle , phosphorus cycle , and oxygen cycle , among others that continually recycle along with other mineral nutrients into productive ecological nutrition. Biogeochemical cycles that are performed by living organisms and natural processes are water , carbon , nitrogen , phosphorus , and sulfur cycles . Nutrient cycles allow these essential elements to return to

6192-700: The cotton gin made the institution increasingly profitable for Southern elites . This sectional conflict regarding slavery culminated in the American Civil War (1861–1865). Eleven slave states seceded and formed the Confederate States of America , while the other states remained in the Union . War broke out in April 1861 after the Confederates bombarded Fort Sumter . After

6321-400: The diet of an organism is the sum of the foods it eats. A healthy diet improves the physical and mental health of an organism. This requires ingestion and absorption of vitamins , minerals , essential amino acids from protein and essential fatty acids from fat-containing food. Carbohydrates , protein and fat play major roles in ensuring the quality of life , health and longevity of

6450-523: The end of the Cold War in 1991, the U.S. emerged as the world's sole superpower , wielding significant geopolitical influence globally . The U.S. national government is a presidential constitutional federal republic and liberal democracy with three separate branches : legislative , executive , and judicial . It has a bicameral national legislature composed of the House of Representatives ,

6579-537: The fall of communism and the collapse of the Soviet Union , which marked the end of the Cold War and left the United States as the world's sole superpower . The 1990s saw the longest recorded economic expansion in American history , a dramatic decline in U.S. crime rates , and advances in technology . Throughout this decade, technological innovations such as the World Wide Web , the evolution of

SECTION 50

#1732801813785

6708-400: The global economy in 2023. It possesses by far the largest amount of wealth of any country and has the highest disposable household income per capita among OECD countries. The U.S. ranks among the world's highest in economic competitiveness , productivity , innovation , human rights , and higher education . Its hard power and cultural influence have a global reach. The U.S. is

6837-402: The soil and the atmosphere. Fungi absorb nutrients around them by breaking them down and absorbing them through the mycelium . Scientific analysis of food and nutrients began during the chemical revolution in the late 18th century. Chemists in the 18th and 19th centuries experimented with different elements and food sources to develop theories of nutrition. Modern nutrition science began in

6966-427: The specific energy (energy per mass) of metabolizing different types of food. For example, fat (triglyceride lipids) contains 9 kilocalories per gram (kcal/g), while carbohydrates (sugar and starch) and protein contain approximately 4 kcal/g. Alcohol in food contains 7 kcal/g. The "large" unit is also used to express recommended nutritional intake or consumption, as in "calories per day". Dieting

7095-813: The 1775 Battles of Lexington and Concord , igniting the American Revolutionary War . At the Second Continental Congress , the colonies appointed George Washington commander-in-chief of the Continental Army , and created a committee that named Thomas Jefferson to draft the Declaration of Independence . Two days after passing the Lee Resolution to create an independent nation the Declaration

7224-404: The 1910s as individual micronutrients began to be identified. The first vitamin to be chemically identified was thiamine in 1926, and vitamin C was identified as a protection against scurvy in 1932. The role of vitamins in nutrition was studied in the following decades. The first recommended dietary allowances for humans were developed to address fears of disease caused by food deficiencies during

7353-520: The 2010s, political polarization in the country increased between liberal and conservative factions. This polarization was capitalized upon in the January 2021 Capitol attack , when a mob of insurrectionists entered the U.S. Capitol and sought to prevent the peaceful transfer of power in an attempted self-coup d'état . The United States is the world's third-largest country by total area behind Russia and Canada. The 48 contiguous states and

7482-419: The 20th century allowed mass production and food fortification to better meet the nutritional needs of humans. Human behavior is closely related to human nutrition, making it a subject of social science in addition to biology. Nutrition in humans is balanced with eating for pleasure, and optimal diet may vary depending on the demographics and health concerns of each person. Humans are omnivores that eat

7611-596: The American West have an alpine climate . The climate is arid in the Southwest, Mediterranean in coastal California , and oceanic in coastal Oregon , Washington , and southern Alaska . Most of Alaska is subarctic or polar . Hawaii , the southern tip of Florida and U.S. territories in the Caribbean and Pacific are tropical . States bordering the Gulf of Mexico are prone to hurricanes, and most of

7740-475: The Declaration of Independence on July 4, 1776. The term "United States" and the initialism "U.S.", used as nouns or as adjectives in English, are common short names for the country. The initialism "USA", a noun, is also common. "United States" and "U.S." are the established terms throughout the U.S. federal government , with prescribed rules. In English, the term "America" rarely refers to topics unrelated to

7869-573: The District of Columbia occupy a combined area of 3,119,885 square miles (8,080,470 km ). The coastal plain of the Atlantic seaboard gives way to inland forests and rolling hills in the Piedmont plateau region. The Appalachian Mountains and the Adirondack massif separate the East Coast from the Great Lakes and the grasslands of the Midwest . The Mississippi River System ,

SECTION 60

#1732801813785

7998-573: The Elder concluded that major military resources needed to be devoted to North America to win the war against France. For the first time, the continent became one of the main theaters of what could be termed a " world war ". The British colonies' position as an integral part of the British Empire became more apparent during the war, with British military and civilian officials becoming a more significant presence in American life. The war increased

8127-683: The January 1863 Emancipation Proclamation , many freed slaves joined the Union army . The war began to turn in the Union's favor following the 1863 Siege of Vicksburg and Battle of Gettysburg , and the Confederacy surrendered in 1865 after the Union's victory in the Battle of Appomattox Court House . The Reconstruction era followed the war. After the assassination of President Abraham Lincoln , Reconstruction Amendments were passed to protect

8256-611: The Rocky Mountains, the Yellowstone Caldera , is the continent's largest volcanic feature. In 2021, the United States had 8% of global permanent meadows and pastures and 10% of cropland. With its large size and geographic variety, the United States includes most climate types. East of the 100th meridian , the climate ranges from humid continental in the north to humid subtropical in the south. The western Great Plains are semi-arid . Many mountainous areas of

8385-647: The U.S. has become a key ally of Ukraine ; it has also provided the country with significant military equipment and other support in response to Russia's 2022 invasion . The president is the commander-in-chief of the United States Armed Forces and appoints its leaders, the secretary of defense and the Joint Chiefs of Staff . The Department of Defense , which is headquartered at the Pentagon near Washington, D.C., administers five of

8514-661: The U.S. territories." Despite disparate systems of confinement, four main institutions dominate: federal prisons , state prisons , local jails, and juvenile correctional facilities . Federal prisons are run by the Federal Bureau of Prisons and hold people who have been convicted of federal crimes, including pretrial detainees. State prisons, run by the official department of correction of each state, hold sentenced people serving prison time (usually longer than one year) for felony offenses. Local jails are county or municipal facilities that incarcerate defendants prior to trial; they also hold those serving short sentences (typically under

8643-416: The United States and the peaceful transfer of power , respectively. The Louisiana Purchase of 1803 from France nearly doubled the territory of the United States. Lingering issues with Britain remained , leading to the War of 1812 , which was fought to a draw. Spain ceded Florida and its Gulf Coast territory in 1819. In the late 18th century, American settlers began to expand westward , many with

8772-541: The United States entered the Cold War, where geopolitical tensions between the U.S. and the Soviet Union led the two countries to dominate world affairs . The U.S. utilized the policy of containment to limit the USSR's sphere of influence, and prevailed in the Space Race , which culminated with the first crewed Moon landing in 1969. Domestically, the U.S. experienced economic growth , urbanization , and population growth following World War II . The civil rights movement emerged, with Martin Luther King Jr. becoming

8901-495: The United States has operated as a de facto two-party system , though the parties in that system have been different at different times. The two main national parties are presently the Democratic and the Republican . The former is perceived as relatively liberal in its political platform while the latter is perceived as relatively conservative . In the American federal system , sovereign powers are shared between two levels of elected government: national and state. People in

9030-402: The United States in 2001 by the pan-Islamist militant organization al-Qaeda led to the war on terror , and subsequent military interventions in Afghanistan and Iraq . The cultural impact of the attacks was profound and long-lasting. The U.S. housing bubble culminated in 2007 with the Great Recession , the largest economic contraction since the Great Depression. Coming to a head in

9159-415: The United States of America to Spain" to seek assistance in the Revolutionary War effort. The first known public usage is an anonymous essay published in the Williamsburg newspaper, The Virginia Gazette , on April 6, 1776. By June 1776, the "United States of America" appeared in the Articles of Confederation and the Declaration of Independence . The Second Continental Congress adopted

9288-593: The United States, despite the usage of "the Americas " as the totality of North and South America. "The States" is an established colloquial shortening of the name, used particularly from abroad; "stateside" is the corresponding adjective or adverb. The first inhabitants of North America migrated from Siberia across the Bering land bridge about 12,000 years ago; the Clovis culture , which appeared around 11,000 BC,

9417-624: The United States, except Iran , North Korea , and Bhutan . Though Taiwan does not have formal diplomatic relations with the U.S., it maintains close unofficial relations. The United States regularly supplies Taiwan with military equipment to deter potential Chinese aggression. Its geopolitical attention also turned to the Indo-Pacific when the United States joined the Quadrilateral Security Dialogue with Australia, India, and Japan. The United States has

9546-509: The United States. The American prison system is largely heterogenous, with thousands of relatively independent systems operating across federal, state, local, and tribal levels. In 2023, "these systems [held] almost 2 million people in 1,566 state prisons, 98 federal prisons, 3,116 local jails, 1,323 juvenile correctional facilities, 181 immigration detention facilities, and 80 Indian country jails, as well as in military prisons , civil commitment centers, state psychiatric hospitals, and prisons in

9675-476: The amount of energy required to raise 1 kilogram of water by 1 degree Celsius. Carbohydrates are molecules that store significant amounts of energy. Animals digest and metabolize carbohydrates to obtain this energy. Carbohydrates are typically synthesized by plants during metabolism, and animals have to obtain most carbohydrates from nature, as they have only a limited ability to generate them. They include sugars , oligosaccharides , and polysaccharides . Glucose

9804-585: The amount of fatty acids it produces as dietary fat intake increases, while it increases the amount of fatty acids it produces as carbohydrate intake increases. Fats contain 9 calories per gram. Protein consumed by animals is broken down to amino acids, which would be later used to synthesize new proteins. Protein is used to form cellular structures, fluids, and enzymes (biological catalysts ). Enzymes are essential to most metabolic processes, as well as DNA replication , repair , and transcription . Protein contains 4 calories per gram. Much of animal behavior

9933-847: The amount of protein in a food. Humans can also obtain energy from ethanol , which is both a food and a drug, but it provides relatively few essential nutrients and is associated with nutritional deficiencies and other health risks. In humans, poor nutrition can cause deficiency-related diseases, such as blindness , anemia , scurvy , preterm birth , stillbirth and cretinism , or nutrient-excess conditions, such as obesity and metabolic syndrome . Other conditions possibly affected by nutrition disorders include cardiovascular diseases , diabetes , and osteoporosis . Undernutrition can lead to wasting in acute cases, and stunting of marasmus in chronic cases of malnutrition. In domesticated animals , such as pets , livestock , and working animals , as well as other animals in captivity , nutrition

10062-477: The amount of time and energy spent foraging. It was created to analyze the foraging habits of animals, but it can also be extended to other organisms. Some organisms are specialists that are adapted to forage for a single food source, while others are generalists that can consume a variety of food sources. Nutrient deficiencies, known as malnutrition , occur when an organism does not have the nutrients that it needs. This may be caused by suddenly losing nutrients or

10191-745: The carbon of other organisms, while autotrophs are organisms that produce their own nutrients from the carbon of inorganic substances like carbon dioxide . Mixotrophs are organisms that can be heterotrophs and autotrophs, including some plankton and carnivorous plants . Phototrophs obtain energy from light, while chemotrophs obtain energy by consuming chemical energy from matter. Organotrophs consume other organisms to obtain electrons, while lithotrophs obtain electrons from inorganic substances, such as water , hydrogen sulfide , dihydrogen , iron(II) , sulfur , or ammonium . Prototrophs can create essential nutrients from other compounds, while auxotrophs must consume preexisting nutrients. In nutrition,

10320-457: The contiguous United States are in the State of California, about 84 miles (135 km) apart. At an elevation of 20,310 feet (6,190.5 m), Alaska's Denali is the highest peak in the country and continent. Active volcanoes are common throughout Alaska's Alexander and Aleutian Islands , and Hawaii consists of volcanic islands. The supervolcano underlying Yellowstone National Park in

10449-556: The country's GDP. The U.S. has 42% of the world's nuclear weapons —the second-largest share after Russia. The United States has the third-largest combined armed forces in the world, behind the Chinese People's Liberation Army and Indian Armed Forces . The military operates about 800 bases and facilities abroad, and maintains deployments greater than 100 active duty personnel in 25 foreign countries. State defense forces (SDFs) are military units that operate under

10578-469: The country's territory would expand with the admission of new states , rather than the expansion of existing states. The U.S. Constitution was drafted at the 1787 Constitutional Convention to overcome the limitations of the Articles. It went into effect in 1789, creating a federal republic governed by three separate branches that together ensured a system of checks and balances . George Washington

10707-713: The development of self-governance, and the First Great Awakening , a series of Christian revivals , fueled colonial interest in religious liberty . For a century, the American colonists had been providing their own troops and materiel in conflicts with indigenous peoples allied with Britain's colonial rivals , especially France, and the Americans had begun to develop a sense of self-defense and self-reliance separate from Britain. The French and Indian War (1754–1763) took on new significance for all North American colonists after Parliament under William Pitt

10836-414: The dispossession of native inhabitants . As more states were admitted , a North–South division over slavery led to the secession of the Confederate States of America , which fought states remaining in the Union in the 1861–1865 American Civil War . With the victory and preservation of the United States, slavery was abolished nationally . By 1900, the country had established itself as a great power ,

10965-492: The environment after being absorbed or consumed. Without proper nutrient cycling, there would be risk of change in oxygen levels, climate, and ecosystem function. Foraging is the process of seeking out nutrients in the environment. It may also be defined to include the subsequent use of the resources. Some organisms, such as animals and bacteria, can navigate to find nutrients, while others, such as plants and fungi, extend outward to find nutrients. Foraging may be random, in which

11094-580: The environment for labor unions to begin to flourish . This period eventually ended with the advent of the Progressive Era , which was characterized by significant reforms. Pro-American elements in Hawaii overthrew the Hawaiian monarchy ; the islands were annexed in 1898. That same year, Puerto Rico , the Philippines , and Guam were ceded to the U.S. by Spain after the latter's defeat in

11223-541: The federal government often applied policies of Indian removal or assimilation . The Trail of Tears (1830–1850) was a U.S. government policy that forcibly removed and displaced most Native Americans living east of the Mississippi River to lands far to the west. These and earlier organized displacements prompted a long series of American Indian Wars west of the Mississippi. The Republic of Texas

11352-606: The first nuclear weapons and used them against the Japanese cities of Hiroshima and Nagasaki in August 1945, ending the war. The United States was one of the " Four Policemen " who met to plan the post-war world , alongside the United Kingdom , Soviet Union , and China . The U.S. emerged relatively unscathed from the war, with even greater economic power and international political influence . After World War II,

11481-665: The first settlement of the Thirteen Colonies in Virginia in 1607. Clashes with the British Crown over taxation and political representation sparked the American Revolution , with the Second Continental Congress formally declaring independence on July 4, 1776. Following its victory in the 1775–1783 Revolutionary War , the country continued to expand westward across North America , resulting in

11610-743: The inability to absorb proper nutrients. Not only is malnutrition the result of a lack of necessary nutrients, but it can also be a result of other illnesses and health conditions. When this occurs, an organism will adapt by reducing energy consumption and expenditure to prolong the use of stored nutrients. It will use stored energy reserves until they are depleted, and it will then break down its own body mass for additional energy. A balanced diet includes appropriate amounts of all essential and non-essential nutrients. These can vary by age, weight, sex, physical activity levels, and more. A lack of just one essential nutrient can cause bodily harm, just as an overabundance can cause toxicity. The Daily Reference Values keep

11739-463: The integration of Army National Guard units and personnel into the U.S. Army and (since 1947) the U.S. Air Force. There are about 18,000 U.S. police agencies from local to national level in the United States. Law in the United States is mainly enforced by local police departments and sheriff departments in their municipal or county jurisdictions. The state police departments have authority in their respective state , and federal agencies such as

11868-487: The large unit. This usage was adopted by Wilbur Olin Atwater , a professor at Wesleyan University , in 1887, in an influential article on the energy content of food. The smaller unit was used by U.S. physician Joseph Howard Raymond , in his classic 1894 textbook A Manual of Human Physiology . He proposed calling the "large" unit "kilocalorie", but the term did not catch on until some years later. The small calorie (cal)

11997-856: The majority of people from nutrient deficiencies. DRVs are not recommendations but a combination of nutrient references to educate professionals and policymakers on what the maximum and minimum nutrient intakes are for the average person. Food labels also use DRVs as a reference to create safe nutritional guidelines for the average healthy person. Animals are heterotrophs that consume other organisms to obtain nutrients. Herbivores are animals that eat plants, carnivores are animals that eat other animals, and omnivores are animals that eat both plants and other animals. Many herbivores rely on bacterial fermentation to create digestible nutrients from indigestible plant cellulose, while obligate carnivores must eat animal meats to obtain certain vitamins or nutrients their bodies cannot otherwise synthesize. Animals generally have

12126-482: The military draft (leading to the end of conscription in 1973) and wide opposition to U.S. intervention in Vietnam (with the U.S. totally withdrawing in 1975). A societal shift in the roles of women was significantly responsible for the large increase in female paid labor participation during the 1970s, and by 1985 the majority of American women aged 16 and older were employed. The late 1980s and early 1990s saw

12255-612: The most attractive to the population are the most vulnerable. The U.S. is one of 17 megadiverse countries containing large numbers of endemic species : about 17,000 species of vascular plants occur in the contiguous United States and Alaska, and over 1,800 species of flowering plants are found in Hawaii, few of which occur on the mainland. The United States is home to 428 mammal species, 784 birds, 311 reptiles, 295 amphibians , and around 91,000 insect species. There are 63 national parks , and hundreds of other federally managed parks, forests, and wilderness areas , managed by

12384-824: The most important. Macronutrients are the primary substances required by an organism, and micronutrients are substances required by an organism in trace amounts. Organic micronutrients are classified as vitamins , and inorganic micronutrients are classified as minerals . Nutrients are absorbed by the cells and used in metabolic biochemical reactions. These include fueling reactions that create precursor metabolites and energy, biosynthetic reactions that convert precursor metabolites into building block molecules, polymerizations that combine these molecules into macromolecule polymers , and assembly reactions that use these polymers to construct cellular structures. Organisms can be classified by how they obtain carbon and energy. Heterotrophs are organisms that obtain nutrients by consuming

12513-662: The most violent, the California genocide of thousands of Native inhabitants, lasted into the early 1870s, just as additional western territories and states were created. During the colonial period, slavery had been legal in the American colonies , though the practice began to be significantly questioned during the American Revolution. States in the North enacted abolition laws , though support for slavery strengthened in Southern states , as inventions such as

12642-433: The organism seeks nutrients without method, or it may be systematic, in which the organism can go directly to a food source. Organisms are able to detect nutrients through taste or other forms of nutrient sensing , allowing them to regulate nutrient intake. Optimal foraging theory is a model that explains foraging behavior as a cost–benefit analysis in which an animal must maximize the gain of nutrients while minimizing

12771-425: The organism. Some cultures and religions have restrictions on what is acceptable for their diet. A nutrient cycle is a biogeochemical cycle involving the movement of inorganic matter through a combination of soil, organisms, air or water, where they are exchanged in organic matter. Energy flow is a unidirectional and noncyclic pathway, whereas the movement of mineral nutrients is cyclic. Mineral cycles include

12900-408: The policy of redlining later adopted by the federal Home Owners' Loan Corporation . An explosion of technological advancement accompanied by the exploitation of cheap immigrant labor led to rapid economic expansion during the late 19th and early 20th centuries , allowing the United States to outpace the economies of England, France, and Germany combined. This fostered the amassing of power by

13029-574: The primary colonial grievances was a denial of their rights as Englishmen , particularly the right to representation in the British government that taxed them . To demonstrate their dissatisfaction and resolve, the First Continental Congress met in 1774 and passed the Continental Association , a colonial boycott of British goods that proved effective. The British attempt to then disarm the colonists resulted in

13158-427: The released nutrients. Predatory strategies of prokaryotes include attaching to the outer surface of the organism and degrading it externally, entering the cytoplasm of the organism, or by entering the periplasmic space of the organism. Groups of predatory prokaryotes may forgo attachment by collectively producing hydrolytic enzymes. United States The United States of America ( USA ), commonly known as

13287-871: The required amount of nutrients causes malnutrition . Nutritional science is the study of nutrition, though it typically emphasizes human nutrition . The type of organism determines what nutrients it needs and how it obtains them. Organisms obtain nutrients by consuming organic matter , consuming inorganic matter, absorbing light, or some combination of these. Some can produce nutrients internally by consuming basic elements, while some must consume other organisms to obtain pre-existing nutrients. All forms of life require carbon , energy , and water as well as various other molecules . Animals require complex nutrients such as carbohydrates , lipids , and proteins , obtaining them by consuming other organisms. Humans have developed agriculture and cooking to replace foraging and advance human nutrition. Plants acquire nutrients through

13416-570: The rights of African Americans . National infrastructure, including transcontinental telegraph and railroads , spurred growth in the American frontier . From 1865 through 1917 an unprecedented stream of immigrants arrived in the United States, including 24.4 million from Europe. Most came through the port of New York City , and New York City and other large cities on the East Coast became home to large Jewish , Irish , and Italian populations, while many Germans and Central Europeans moved to

13545-614: The rocky Great Basin and Chihuahua , Sonoran , and Mojave deserts. In the northwest corner of Arizona , carved by the Colorado River over millions of years, is the Grand Canyon , a steep-sided canyon and popular tourist destination known for its overwhelming visual size and intricate, colorful landscape. The Sierra Nevada and Cascade mountain ranges run close to the Pacific coast . The lowest and highest points in

13674-897: The root-like mycelium, which grows through the organism's source of nutrients and can extend indefinitely. The fungus excretes extracellular enzymes to break down surrounding matter and then absorbs the nutrients through the cell wall. Fungi can be parasitic, saprophytic, or symbiotic. Parasitic fungi attach and feed on living hosts, such as animals, plants, or other fungi. Saprophytic fungi feed on dead and decomposing organisms. Symbiotic fungi grow around other organisms and exchange nutrients with them. Protists include all eukaryotes that are not animals, plants, or fungi, resulting in great diversity between them. Algae are photosynthetic protists that can produce energy from light. Several types of protists use mycelium similar to those of fungi. Protozoa are heterotrophic protists, and different protozoa seek nutrients in different ways. Flagellate protozoa use

13803-433: The safety, quality, flavor, and nutritional content of food. Humans obtain most carbohydrates as starch from cereals, though sugar has grown in importance. Lipids can be found in animal fat , butterfat , vegetable oil, and leaf vegetables , and they are also used to increase flavor in foods. Protein can be found in virtually all foods, as it makes up cellular material, though certain methods of food processing may reduce

13932-573: The six service branches, which are made up of the U.S. Army , Marine Corps , Navy , Air Force , and Space Force . The Coast Guard is administered by the Department of Homeland Security in peacetime and can be transferred to the Department of the Navy in wartime. The United States spent $ 916 billion on its military in 2023, which is by far the largest amount of any country , making up 37% of global military spending and accounting for 3.4% of

14061-437: The small unit; the "large" unit being generally called "kilocalorie" with symbol "kcal". It is mostly used to express the amount of energy released in a chemical reaction or phase change , typically per mole of substance, as in kilocalories per mole . It is also occasionally used to specify other energy quantities that relate to reaction energy, such as enthalpy of formation and the size of activation barriers . However, it

14190-474: The soil as phosphates , boric acid , and silicic acid , respectively. Other nutrients used by plants are potassium, sodium, calcium, magnesium, manganese, chlorine, iron, copper, zinc, and molybdenum. Plants uptake essential elements from the soil through their roots and from the air (consisting of mainly nitrogen and oxygen) through their leaves . Nutrient uptake in the soil is achieved by cation exchange , wherein root hairs pump hydrogen ions (H ) into

14319-528: The soil in which they grow. This is made possible by the fact that largely inert atmospheric nitrogen is changed in a nitrogen fixation process to biologically usable forms in the soil by bacteria. As these nutrients do not provide the plant with energy, they must obtain energy by other means. Green plants absorb energy from sunlight with chloroplasts and convert it to usable energy through photosynthesis . Fungi are chemoheterotrophs that consume external matter for energy. Most fungi absorb matter through

14448-471: The soil through proton pumps . These hydrogen ions displace cations attached to negatively charged soil particles so that the cations are available for uptake by the root. In the leaves, stomata open to take in carbon dioxide and expel oxygen . Although nitrogen is plentiful in the Earth's atmosphere, very few plants can use this directly. Most plants, therefore, require nitrogen compounds to be present in

14577-545: The sole authority of a state government. SDFs are authorized by state and federal law but are under the command of the state's governor . They are distinct from the state's National Guard units in that they cannot become federalized entities. A state's National Guard personnel, however, may be federalized under the National Defense Act Amendments of 1933 , which created the Guard and provides for

14706-465: The solution in kelvins or degrees Celsius. However, this estimate assumes that the volumetric heat capacity of the solution is 1 kcal/( L ⋅ K ), which is not exact even for pure water. Nutrition Nutrition is the biochemical and physiological process by which an organism uses food to support its life . It provides organisms with nutrients , which can be metabolized to create energy and chemical structures. Failure to obtain

14835-543: The states are also represented by local elected governments , which are administrative divisions of the states. States are subdivided into counties or county equivalents , and further divided into municipalities . The District of Columbia is a federal district containing the U.S. capital, Washington, D.C. . The federal district is an administrative division of the federal government. Federally recognized tribes govern 326 Indian reservations . The United States has an established structure of foreign relations, and it has

14964-510: The structure and responsibilities of the national federal government and its relationship with the individual states. The U.S. Constitution is the world's oldest national constitution still in effect (from March 4, 1789). Composed of three branches, all headquartered in Washington, D.C., the federal government is the national government of the United States. It is regulated by a strong system of checks and balances . The three-branch system

15093-505: The symbol Cal (both with a capital C) if the large calorie is meant, to avoid confusion; however, this convention is often ignored. In physics and chemistry , the word calorie and its symbol usually refer to the small unit, the large one being called kilocalorie (kcal). However, the kcal is not officially part of the International System of Units (SI), and is regarded as obsolete, having been replaced in many uses by

15222-516: The unit kilocalorie to the unit kilojoules, whereas most physiologists prefer to use kilojoules. In the majority of other countries, nutritionists prefer the kilojoule to the kilocalorie. In the European Union , on nutrition facts labels , energy is expressed in both kilojoules and kilocalories, abbreviated as "kJ" and "kcal" respectively. In China , only kilojoules are given. The unit is most commonly used to express food energy , namely

15351-582: The world's fourth-longest river system , runs predominantly north–south through the heart of the country. The flat and fertile prairie of the Great Plains stretches to the west, interrupted by a highland region in the southeast. The Rocky Mountains , west of the Great Plains, extend north to south across the country, peaking at over 14,000 feet (4,300 m) in Colorado . Farther west are

15480-583: The world's second-largest diplomatic corps as of 2024 . It is a permanent member of the United Nations Security Council , and home to the United Nations headquarters . The United States is a member of the G7 , G20 , and OECD intergovernmental organizations. Almost all countries have embassies and many have consulates (official representatives) in the country. Likewise, nearly all countries host formal diplomatic missions with

15609-461: The world's third-largest land area , largest exclusive economic zone , and third-largest population , exceeding 334 million. Its three largest metropolitan areas are New York , Los Angeles , and Chicago , and its three most populous states are California , Texas , and Florida . Paleo-Indians migrated across the Bering land bridge more than 12,000 years ago, and formed various civilizations and societies . British colonization led to

15738-444: The world's oldest surviving federation, and its presidential system of national government has been adopted, in whole or in part, by many newly independent states worldwide following their decolonization . It is a liberal representative democracy "in which majority rule is tempered by minority rights protected by law ". The Constitution of the United States serves as the country's supreme legal document , also establishing

15867-553: The world's tornadoes occur in the country , mainly in Tornado Alley . Overall, the United States receives more high-impact extreme weather incidents than any other country. Extreme weather became more frequent in the U.S. in the 21st century, with three times the number of reported heat waves as in the 1960s. In the American Southwest , droughts became more persistent and more severe. The regions considered as

15996-575: Was annexed in 1845, and the 1846 Oregon Treaty led to U.S. control of the present-day American Northwest . Victory in the Mexican–American War resulted in the 1848 Mexican Cession of California, Nevada, Utah, and much of present-day Colorado and the American Southwest . The California gold rush of 1848–1849 spurred a huge migration of white settlers to the Pacific coast, leading to even more confrontations with Native populations. One of

16125-759: Was adopted on July 4, 1776. The political values of the American Revolution included liberty , inalienable individual rights ; and the sovereignty of the people ; supporting republicanism and rejecting monarchy , aristocracy , and all hereditary political power; civic virtue ; and vilification of political corruption . The Founding Fathers of the United States , who included Washington, Jefferson, John Adams , Benjamin Franklin , Alexander Hamilton , John Jay , James Madison , Thomas Paine , and many others, were inspired by Greco-Roman , Renaissance , and Enlightenment philosophies and ideas. The Articles of Confederation were ratified in 1781 and established

16254-583: Was elected the country's first president under the Constitution, and the Bill of Rights was adopted in 1791 to allay skeptics' concerns about the power of the more centralized government. His resignation as commander-in-chief after the Revolutionary War and his later refusal to run for a third term as the country's first president established a precedent for the supremacy of civil authority in

16383-598: Was first introduced by Nicolas Clément , as a unit of heat energy, in lectures on experimental calorimetry during the years 1819–1824. This was the "large" calorie. The term (written with lowercase "c") entered French and English dictionaries between 1841 and 1867. The same term was used for the "small" unit by Pierre Antoine Favre (chemist) and Johann T. Silbermann (physicist) in 1852. In 1879, Marcellin Berthelot distinguished between gram-calorie and kilogram-calorie, and proposed using "Calorie", with capital "C", for

16512-459: Was recognized as a unit of the CGS system in 1896, alongside the already-existing CGS unit of energy, the erg (first suggested by Clausius in 1864, under the name ergon , and officially adopted in 1882). In 1928, there were already serious complaints about the possible confusion arising from the two main definitions of the calorie and whether the notion of using the capital letter to distinguish them

16641-461: Was sound. The joule was the officially adopted SI unit of energy at the ninth General Conference on Weights and Measures in 1948. The calorie was mentioned in the 7th edition of the SI brochure as an example of a non-SI unit. The alternate spelling calory is a less-common, non-standard variant. The "small" calorie is broadly defined as the amount of energy needed to increase the temperature of 1 gram of water by 1 °C (or 1 K, which

#784215