Suppose you experience hearing loss from listening to loud music. which kind of factor is loud music?
a part of the social environmentb art of the physical environment c related to available healthcare d an inherited trait

The answer is A: part of the social environment 

Ican only answer your first question, a machine is like a human body because it's a little similar. they both almost work like the same.

(a) is not correct because one does not get increased cholesterol  from lifting weights.(b) is not correct because lifting weights cannot reduce the risk of a hereditary disease.(c) is not correct because back pain isn't a benefit! and plus, if he lifts weights properly, he should not have back pain.(d) is the correct answer because his ligaments will gain mass, making it easier for him to carry heavier weights and he will also be stronger!