4) All of the following are sources of air pollution, EXCEPT
a. chlorofluorocarbons (CFCs).
b. heavy metals such as mercury.
c. nitrogen oxides from automotive exhaust.
d. small particles of smoke and dust in smog.

Respuesta :

With the choices given, the answer to the biology question presented above would be b. heavy metals such as mercury. Heavy metals contribute to soil pollution more than air pollution. The other choices are sources of air pollution. Thus, letter b is the answer.

Heavy metal such as mercury. Mercury is an aquatic pollutant. A by-product from fuels, it is taken up into the food chain and makes seafood and lake food unsafe to eat in some areas.