Which of the following is a method by which helminths are transmitted?

soil
neither air nor soil
air
both air and soil

soil

Explanation:

its transmitted by the parasites and worms laying eggs

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.

i think the answer is b.