【单选题】An understanding of man's effect on the balance of nature is crucial(关键的)to being able to find the appropriate remedial action. It is a very common belief that the problems of the population explosion...
A.
poor people in poor countries contribute to the imbalance of nature
B.
rich people know how to protect the environment by taking actions
C.
people in poor areas know a lot about the birth control
D.
rich people in rich countries have done a lot to balance nature