Tropical rain forests once covered more than __(a)__ percent of the earth surface, now covers not more than __(b)__ percent.

	a	b
1.	30	19.8
2.	8.1	2.4
3.	14	6
4.	19.8	8.1

Tropical rain forests used to cover more than 14 per cent of the earth surface. Now, due to human activities leading to destruction of habitat and pushing many species to the brink of extinction has tropical rainforests cover no more than 6 percent.