What do you think is the most important structure in the urinary system?

The kidneys are the most important structure, because they regulate your blood, and they're responsible for your waste products.

Two urinaters and the bladder. the urinators are tubes that carry urine to the bladder

(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!