The nitrogen cycle is an example of a(n) (biogeochemical / decomposer)

significant amounts of nitrogen oxides, carbon monoxide, and other pollution

explanation:

passenger vehicles are a major pollution contributor, producing significant amounts of nitrogen oxides, carbon monoxide, and other pollution. in 2013, transportation contributed more than half of the carbon monoxide and nitrogen oxides, and almost a quarter of the hydrocarbons emitted into our air.

your body is trying to warm itself up. or more precisely, sensors in your skin send messages to your brain to generate heat to your body.

bacterium is not correct

the answer is 100% density i've answered this question before and done the quiz myself.