Generate a sentence that answers this question: "many vehicles emitting pollution into the air may occur when".

Answer: many vehicles emit pollution into the air

Generate a sentence that answers this question: "Peddling a bicycle can be accomplished by".

Answer: a human can pedal a bicycle

Generate a sentence that answers this question: "As a result of decreased water, what will happen to tree rings?".

Answer:
as the amount of available water decreases , tree-growth rings will become narrower