Permanent hardness of water, due to sulphates of the metal, can be destroyed by the use of

The marine animal called dugong which is vulnerable to extinction is a/an

The hardest substance available on earth is

When a gas is turned into a liquid, the process is called

A hypothesis is _______.

Environmental science is a __________.

Water is unique because no other substance occurs in ________.

Thunderstorms are violent ________ storms accompanied by thunder and lightning.

This graph depicting island diversity predicts that ________.

The thermosphere has _____ air pressure than the mesosphere. more less equal

The thermohaline circulation belt _____.