For which of the following reasons can natural pollutants play an important role in controlling air pollution?
A. They have existed since the Earth developed.
B. They occur in greater quantities than other pollutants.
C. They are less harmful to living beings than other pollutants.
Chọn đáp án D
Câu hỏi trên thuộc đề trắc nghiệm dưới đây !
Copyright © 2021 HOCTAP247