Question

read the passage. then answer the question.
people first flew in a hot - air balloon, not an airplane. this is because the technology behind hot - air balloons is very simple. a burner sends flames into the balloon which fill it with hot air. this makes the balloon rise because hot air is lighter than cool air. when the burner is turned off and the air inside is cooled, the balloon goes down. balloon pilots catch different winds that are blowing. this lets them steer the balloon where they want it to go.
highlight the sentence that tells why pilots catch different winds.
when the burner is turned off and the air inside is cooled, the balloon goes down. balloon pilots catch different winds that are blowing. this lets them steer the balloon where they want it to go.

Explanation:

The sentence "This lets them steer the balloon where they want it to go" explains the reason (purpose) behind pilots catching different winds.

Answer:

This lets them steer the balloon where they want it to go.