Passage OneIn many countries today, laws p

问题：

Passage One

In many countries today, laws protect wildlife. In India the need for such protection was realized centuries ago.

About 300 B. C. an Indian writer described forests that were somewhat like national parks today. The killing of game animals was carefully governed. Some animals were fully protected. Within the forest, nobody was allowed to cut trees, burn wood, or trap animals for their furs. Animals that became dangerous to human visitors were trapped or killed outside the park, so that other animals would not become uneasy.

The need for wildlife protection is greater now than ever before. About a thousand sorts of animals are in danger of extinction, and the speed at which they are being destroyed has been putting on. With mammals, for example, the speed of extinction is now about one sort every year; from A. D. 1 to 1800, the speed was about one sort ever), fifty years. Everywhere, men are trying to solve the problem of saving wildlife while caring for the world’s growing population.

The word" extinetion"in this report most properly means“（）”.

A．falling down

B．dying out

C．growing up

D．going away