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Philip II, king of Macedon

(Encyclopedia)Philip II, 382–336 b.c., king of Macedon (359–336 b.c.), son of Amyntas II. While a hostage in Thebes (367–364), he gained much knowledge of Greece and its people. He was appointed regent for Am...

radiation sickness

(Encyclopedia)radiation sickness, harmful effect produced on body tissues by exposure to radioactive substances. The biological action of radiation is not fully understood, but it is believed that a disturbance in ...

osteoporosis

(Encyclopedia)osteoporosis ŏsˌtēōˌpərōˈsĭs [key], disorder in which the normal replenishment of old bone tissue is severely disrupted, resulting in weakened bones and increased risk of fracture; osteopenia...

adaptation

(Encyclopedia)adaptation, in biology, has several meanings. It can mean the adjustment of living matter to environmental conditions and to other living things either in an organism's lifetime (physiological adaptat...

protozoan

(Encyclopedia)protozoan prōˌtəzōˈən [key], informal term for the unicellular heterotrophs of the kingdom Protista. Protozoans comprise a large, diverse assortment of microscopic or near-microscopic organisms ...

uranium

(Encyclopedia)uranium yo͞orāˈnēəm [key], radioactive metallic chemical element; symbol U; at. no. 92; mass number of most stable isotope 238; m.p. 1,132℃; b.p. 3,818℃; sp. gr. 19.1 at 25℃; valence +3, +4...

Giuliani, Rudolph William

(Encyclopedia)Giuliani, Rudolph William jo͞oˌlē-äˈnē [key], 1944–, American government official, b. Brooklyn, N.Y. He attended Manhattan College and studied law at New York Univ. In the Justice Dept. as ass...

aquaculture

(Encyclopedia)aquaculture, the raising and harvesting of fresh- and saltwater plants and animals. The most economically important form of aquaculture is fish farming, an industry that accounts for an ever increasin...

arteriosclerosis

(Encyclopedia)arteriosclerosis ärtĭrˌēōsklərōˈsis [key], general term for a condition characterized by thickening, hardening, and loss of elasticity of the walls of the blood vessels. These changes are freq...

glacial periods

(Encyclopedia)glacial periods, times during which large portions of the earth's surface were covered with thick glacial ice sheets. In the Pleistocene epoch, in the Carboniferous and Permian periods of the Paleozoi...