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.

What evidence supports the law of conservation of energy? a) mechanical energy is converted to chemical energy during photosynthesis. b) oxygen is made from the breakdown of carbon dioxide during photosynthesis. c)energy is absorbed by chlorophyll and becomes chemical energy during photosynthesis. d)the sun gives off light energy that is absorbed by plants.

Viruses can be transmitted through air, water, food, insect bites, and direct skin contact. once a virus gains entry into the body, it invades a host cell in order to? a. synthesize antibodies for defense b. deactivate the host cell's defenses c. access cell processes for reproduction d. metabolize host proteins and grow

The source of energy shown in the image is (renewable, non renewable, polluting) a drawback of building a dam is that (it will destroy ecosystems, it requires fossil fuels, it won’t be useful for irrigation)