Which of the following is true about water resources?

a very small proportion of freshwater is effectively available for human use.

The correct answer is Option 3: a very small proportion of freshwater is effectively available for human use.

Option 1: Approximately, 65 per cent of the earth’s surface is covered with water. This statement is incorrect. Approximately, 71 per cent of the earth’s surface is covered with water.

Option 2: Freshwater constitutes only about 24 per cent of the total water available on earth. This statement is incorrect. Freshwater constitutes only about 3 per cent of the total water available on Earth, not 24 per cent.

Option 3: A very small proportion of freshwater is effectively available for human use. This statement is also correct. Even though there is a significant amount of water on Earth, most of it is inaccessible. Fresh water accounts for only about 3% of all water on Earth. Of that 3%, nearly 69% is locked in glaciers and ice caps, and about 30% is underground. This leaves less than 1% of all fresh water (found in lakes, rivers, and the atmosphere) easily accessible for human use and ecosystems.

NCERT: "Approximately, 71 per cent of the earth’s surface is covered with it but freshwater constitutes only about 3 per cent of the total water. In fact, a very small proportion of freshwater is effectively available for human use."