Question

8. Two-thirds of the earth's surface is covered with water. Then why should we conserve water​

Answer 1

Explanation:

the two third water is 90% salty water ...which is of no use for humans

Answer 2

Yes it's right that two third of the earth surface is covered with water but only 2.5–2.75% is freshwater of which 1.75–2.00% is Frozen in glaciers and ice caps and rest only 0.5–0.75% is available for human use and is available as ground freshwater. 97% of the water is salty and is not fit for usage.