The roots of the trees are damaged due to the acid rain which causes leaching away of:

The argon content in clean air.

Which of the following  gives power to the rock cycle?

If a lake ecosystem is overloaded by nutrients , it increases the growth of plants and:

Which are not removed by water treatment?

The atmosphere of the earth is different from that of its neighbor because of the presence of:

The boiling point of oxygen, nitrogen, argon and neon are -183^o C , - 196^oC and -246^oC respectively. Which of these has lowest boiling points ?

Plant life developed in warm shallows seas. What did they release into the atmosphere after using carbon dioxide?

The water vapour condensed and fell back to the surface, forming the first:

Which is used in cryogenics?