The best answer to the question above would be letter c. The mode of exercise refers to the <em>type </em>of exercise performed. These are exercises that fall under categories such as strength, flexibility, agility training and all those categories of exercises for the sake of training for function.
It's C because kidneys remove and filter out waste from blood and urine.
Oxygen transport and storage
(ik I gave three but just use two of them if you want)
To remove a poisonous or harmful substance or a treatment for them to be removed.
