Question: Census data show that the human population doubled from 2.65 billion in 1953 to 5.3 billion in 1990. If it continues to double at this rate, the human population could reach 10 billion by the year 2020. Which best explains how this rate of human growth can harm the environment on which humans depend?

  Options: 
 A. by gradually making up more available energy
 B. by using resources faster than they can be replaced
 C. by changing how matter cycles through an ecosystem
 D. by increasing the variety of ecosystems that are supported
Answer: B