exchange gases. break down nutrients. filter wastes and byproducts. carry blood back to the heart.
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: The major function of the kidneys is to
Possibilities:
- exchange gases.
- break down nutrients.
- filter wastes and byproducts.
- carry blood back to the heart.

filter wastes and byproducts.