Question 1

What process involves the continuous movement of water through the atmosphere, land, and ocean?

Accepted Answer

The correct answer is the Water cycle. The water cycle is the continuous movement of water on, above, and below the surface of the Earth, changing its form between liquid, vapor, and ice.

Question 2

Approximately what percentage of the earth's surface is covered with water?

Accepted Answer

The correct answer is 71 percent. About three-fourths or 71 percent of the earth's surface is covered with water, making Earth appear blue from space.

Question 3

What is the primary source of freshwater on the earth?

Accepted Answer

The correct answer is glaciers and ice caps. The major part of freshwater is locked in ice caps and glaciers in Antarctica, Greenland, and mountain peaks.

Question 4

What percentage of total water on earth is available as freshwater suitable for human use?

Accepted Answer

The correct answer is about 2.7 percent. Out of total water, about 97.3% is saline and only about 2.7% is freshwater, of which a large portion is trapped in ice.

Question 5

What causes ocean water to be saline?

Accepted Answer

The correct answer is high amount of dissolved salts. Ocean water contains large amounts of dissolved salts, primarily sodium chloride (common salt), washed down from the land.

Water — NCERT Class 7 Social Science Important Questions & Revision Notes