Question

1. Why is it not possible to use all the water found
on the Earth's surface directly?​

Answer 1

Answer:

it's not safe to use water directly as it may contain many impurities and can prove to be harmful to human life. therefore water is always purified before using

Answer 2

Answer:

The water present on earth i.e in seas and oceans contains impurities such as magnesium and sodium salts and also other microbiological impurities which are harmful for our health. That's why we can't use water from these sources