Question

2 - air pollution
learning objective: differentiate between the three sources of air pollution.
examples of mobile sources of outdoor air pollution are ____________.
a.) buses and trucks
b.) forest fires and volcanoes
c.) factories and refineries
d.) dry cleaners and gas stations

Explanation:

Mobile sources of outdoor air - pollution are those that are movable. Buses and trucks are vehicles that can move and emit pollutants like carbon - monoxide, particulate matter etc. Forest fires and volcanoes are natural sources, factories and refineries are stationary sources, and dry cleaners and gas stations are also stationary sources of pollution.

Answer:

A. buses and trucks