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gills, in biology

(Encyclopedia)CE5 Gills of a fish: Side view (A) and ventral view (B) gills, external respiratory organs of most aquatic animals. In fishes the gills are located in gill chambers at the rear of the mouth (phary...

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,...

Haldane, John Scott

(Encyclopedia)Haldane, John Scott, 1860–1936, British scientist, b. Edinburgh; father of John Burdon Sanderson Haldane. He made many important contributions to mine safety, investigating principally the action of...

sublimation, in chemistry

(Encyclopedia)sublimation sŭblĭmāˈshən [key], change of a solid substance directly to a vapor without first passing through the liquid state. The term is also used to describe the reverse process of the gas ch...

capillary

(Encyclopedia)capillary kăpˈəlĕrˌē [key], microscopic blood vessel, smallest unit of the circulatory system. Capillaries form a network of tiny tubes throughout the body, connecting arterioles (smallest arter...

Liebig, Justus, Baron von

(Encyclopedia)Liebig, Justus, Baron von yo͝osˈto͝os bärônˈ fən lēˈbĭkh [key], 1803–73, German chemist. As professor at Giessen (1824–52), he was among the first to establish a chemical teaching labora...

excretion

(Encyclopedia)excretion, process of eliminating from an organism waste products of metabolism and other materials that are of no use. It is an essential process in all forms of life. In one-celled organisms wastes ...

gallic acid

(Encyclopedia)gallic acid or 3,4,5-trihydroxybenzoic acid trīˌhīdrŏkˈsēbĕnzōˈĭk [key], C6H2(OH)3CO2H, colorless crystalline organic acid found in gallnuts, sumach, tea leaves, oak bark, and many other pla...

methane

(Encyclopedia)methane mĕthˈān [key], CH4, colorless, odorless, gaseous saturated hydrocarbon; the simplest alkane. It is less dense than air, melts at −184℃, and boils at −161.4℃. It is combustible and c...

hydrocarbon

(Encyclopedia)hydrocarbon hīˌdrōkärˈbən [key], any organic compound composed solely of the elements hydrogen and carbon. The hydrocarbons differ both in the total number of carbon and hydrogen atoms in their ...