Which of these is an example of a chemical change?
a. burning a piece of wood
b. breaking a tree branch
c. dissolving salt in water
d. melting water

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.

hello there the answer is d