QUESTION 14 Scientists state that burning fossil fuels is a big threat to our clean air. What else could be a threat to our supply of clean air?

Vehicle exhaust fumes are also a threat to our air supply of clean air. It is means of transportation for a majority of the population whether it is a personal car or a ride on public transportation. It produces carbon dioxide and other greenhouse gases that keep heat trapped in the earth’s atmosphere.

The answer is c i just finished taking the test