Why is carbon-dioxide gas used to extinguish fire?

Air is a mixture. Prove this statement.

Explain why during an incident of fire, one is advised to wrap a woollen blanket over a burning object.

Explain why mountaineers carry oxygen cylinders with them?

Why do we see the sky and air clear and clean after rainfall?

How will you prove that soil contains air in it?

You must have seen during rainy season, when it rains the animals like earthworm, snakes, snails etc. are commonly seen. Explain why?

What happens if the percentage of carbon-dioxide increases in the air?

What happens if the percentage of oxygen in the air reaches to 70%?

Describe balance of oxygen in the air.

Mention two uses of air.