4. Acid rain is formed due to the contribution from the following pair of gases: 1) Methane and ozone
2) Oxygen and nitrous oxide
3) Methane and sulphur dioxide
4) Carbon dioxide and sulphur dioxide

In 1915 the german geologist and meteorologist alfred wegener first proposed the theory of continental drift, which states that parts of the earth's crust slowly drift atop a liquid core. the fossil record supports and gives credibility to the theories of continental drift and plate tectonics.

How many countries have portuguese as a national language?

What is the northern most national park in the world