As the human population grows, what happens to our natural-resource requirements?
a. they increase.
b. they decrease.
c. they do not change.
d. they go in cycles.

As the human population grow, the natural resource requirements INCREASES. The correct option is A. 
More than ever before, the number of people that are living on the earth has increased tremendously and this has put a great pressure on the basic materials that are needed by humans, one of these is natural resources.
Human natural resources requirement refers to the amount of natural resources that is adequate for human's use. There are many natural resources, which man use for different purposes. Most of these resource are already diminishing yet the population of man keep increasing. Thus, man need more natural resources.