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Permian period

(Encyclopedia)Permian period pûrˈmēən [key] [from Perm, Russia], sixth and last period of the Paleozoic era (see Geologic Timescale, tablegeologic timescale, table) from 250 to 290 million years ago. Many ma...

Cairo, city, Egypt

(Encyclopedia)Cairo kīˈrō [key], Arab. Al Qahirah, city (2021 est. metro. area pop. 21,323,000), capital...

air navigation

(Encyclopedia)air navigation, science and technology of determining the position of an aircraft with respect to the surface of the earth and accurately maintaining a desired course (see navigation). Basic to air ...

Carboniferous period

(Encyclopedia)Carboniferous period kärbənĭfˈərəs [key], fifth period of the Paleozoic era of geologic time (see Geologic Timescale, tablegeologic timescale, table), from 350 to 290 million years ago. The pl...

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,...

Islam

(Encyclopedia)Islam ĭslämˈ, ĭsˈläm [key], [Arab.,=submission to God], world religion founded by the Prophet Muhammad. Founded in the 7th cent., Islam is the youngest of the three monotheistic world religions ...

birth control

(Encyclopedia)birth control, practice of contraception for the purpose of limiting reproduction. Although contraceptive techniques had been known in ancient Egypt, Greece, and Rome, the modern movement for birth ...

Kuomintang

(Encyclopedia)Kuomintang gwōˈmĭnˈdängˈ, kwōˈmĭntăngˈ [key] [Chin.,=national people's party] (KMT), Chinese and Taiwanese political party. Sung Chiao-jen organized the party in 1912, under the nominal lea...

mutation

(Encyclopedia)mutation, in biology, a sudden, random change in a gene, or unit of hereditary material, that can alter an inheritable characteristic. Most mutations are not beneficial, since any change in the delica...

diplomatic service

(Encyclopedia)diplomatic service, organized body of agents maintained by governments to communicate with one another. In the 20th and 21st cent. there have been numerous meetings of heads of state and foreign min...