One thing people in the united states could do to reduce air pollution is a. drive their cars more. b. burn more fossil fuels. c. use more public transportation. d. build more factories.

c. use more public transportation

Public transportation, even though it is somewhat inconvenient (sometimes) actually help reduce air pollution, because it is able to bring many people from a certain destination to another, which lessens the need to drive your own car (which emits pollution), and is able to do the same job for more people, with less pollution (by the proportions)

hope this helps

Cells of an organism tell each other when predators are near.