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global warming

(Encyclopedia)global warming, the gradual increase of the temperature of the earth's lower atmosphere as a result of the increase in greenhouse gases since the Industrial Revolution. Global warming and its effects,...

agriculture

(Encyclopedia)agriculture, science and practice of producing crops and livestock from the natural resources of the earth. The primary aim of agriculture is to cause the land to produce more abundantly and at the sa...

Indo-Iranian

(Encyclopedia)Indo-Iranian, subfamily of the Indo-European family of languages, spoken by more than a billion people, chiefly in Afghanistan, Bangladesh, India, Iran, Nepal, Pakistan, and Sri Lanka (see The Indo-Eu...

American Federation of Labor and Congress of Industrial Organizations

(Encyclopedia)American Federation of Labor and Congress of Industrial Organizations (AFL-CIO), a federation of autonomous labor unions in the United States, Canada, Mexico, Panama, and U.S. dependencies, formed in ...

AIDS, in medicine

(Encyclopedia)AIDS or acquired immunodeficiency syndrome, fatal disease caused by a rapidly mutating retrovirus that attacks the immune system and leaves the victim vulnerable to infections, malignancies, and neuro...

biography

(Encyclopedia)biography, reconstruction in print or on film, of the lives of real men and women. Together with autobiography—an individual's interpretation of his own life—it shares a venerable tradition, meeti...

Obama, Barack

(Encyclopedia)Obama, Barack (Barack Hussein Obama 2d), bəräkˈ ho͞osānˈ ōbäˈmə [key], 1961–, 44th president of the United States (2009–17), b. Honolulu, grad. Columbia (B.A. 1983), Harvard Law School ...

marijuana

(Encyclopedia)marijuana or marihuana, drug obtained from the flowering tops, stems, and leaves of the hemp plant, Cannabis sativa (see hemp) or C. indica; the latter species can withstand colder climates. It is one...

air pollution

(Encyclopedia)air pollution, contamination of the air by noxious gases and minute particles of solid and liquid matter (particulates) in concentrations that endanger health. The major sources of air pollution are t...

rock music

(Encyclopedia)rock music, type of music originating in the United States in the mid-1950s and increasingly popular throughout much of the world. A turning point in rock music occurred in the mid-1970s in the ...