biological activity of soils
61South America — South American. a continent in the S part of the Western Hemisphere. 271,000,000; ab. 6,900,000 sq. mi. (17,871,000 sq. km). * * * Continent, Western Hemisphere. The world s fourth largest continent, it is bounded by the Caribbean Sea to the… …
62hydrosphere — /huy dreuh sfear /, n. the water on or surrounding the surface of the globe, including the water of the oceans and the water in the atmosphere. [1885 90; HYDRO 1 + SPHERE] * * * Discontinuous layer of water at or near the Earth s surface. It… …
63North America — North American. the northern continent of the Western Hemisphere, extending from Central America to the Arctic Ocean. Highest point, Mt. McKinley, 20,300 ft. (6187 m); lowest, Death Valley, 276 ft. (84 m) below sea level. 400,000,000 including… …
64plant disease — ▪ plant pathology Introduction an impairment of the normal state of a plant that interrupts or modifies its vital functions. All species of plants, wild and cultivated alike, are subject to disease. Although each species is… …
65United Kingdom — a kingdom in NW Europe, consisting of Great Britain and Northern Ireland: formerly comprising Great Britain and Ireland 1801 1922. 58,610,182; 94,242 sq. mi. (244,100 sq. km). Cap.: London. Abbr.: U.K. Official name, United Kingdom of Great… …
66Asia — /ay zheuh, ay sheuh/, n. a continent bounded by Europe and the Arctic, Pacific, and Indian oceans. 2,896,700,000; ab. 16,000,000 sq. mi. (41,440,000 sq. km). * * * I Largest continent on Earth. It is bounded by the Arctic Ocean, the Pacific Ocean …
67Europe, history of — Introduction history of European peoples and cultures from prehistoric times to the present. Europe is a more ambiguous term than most geographic expressions. Its etymology is doubtful, as is the physical extent of the area it designates.… …
68Antarctica — /ant ahrk ti keuh, ahr ti /, n. the continent surrounding the South Pole: almost entirely covered by an ice sheet. ab. 5,000,000 sq. mi. (12,950,000 sq. km). Also called Antarctic Continent. * * * Antarctica Introduction Antarctica Background:… …
69biosphere — biospheric /buy euh sfer ik/, adj. /buy euh sfear /, n. 1. the part of the earth s crust, waters, and atmosphere that supports life. 2. the ecosystem comprising the entire earth and the living organisms that inhabit it. [1895 1900; < G Biosphäre; …
70geology — /jee ol euh jee/, n., pl. geologies. 1. the science that deals with the dynamics and physical history of the earth, the rocks of which it is composed, and the physical, chemical, and biological changes that the earth has undergone or is… …
