The earth has a tremendous amount of water, but almost (1). . . . . . . . . is in the oceans. The oceans (2). . . . . . . . . about 70 percent of the earth’s surface. They (3). . . . . . . . . . about 97 percent of all the water on earth, and are the source of (4). . . . . . . . . . precipitation that falls to earth. Ocean water is (5). . . . . . . . . to be used (6). . . . . . . . , agriculture, or industry. But the salt is left (7). . . . . . . . during evaporation, and the precipitation that falls to earth is unsalty water.
Only about 3 percent of the water on earth is fresh water and most of it is not easily (8). . . . . . . . . . to man. It includes water locked in (9). . . . . . . . . and ice-caps, more than 2 percent of the earth’s surface. About half of 1 percent of the earth’s water is beneath the earth’s surface. Rivers and lakes contain only about (10). . . . . . . . of 1 percent of the earth’s water.
