C is the answer :D hope you pass your test
Answer:
C. circulatory and respiratory
Explanation:
The respiratory system is a system that is directly related to breathing and circulatory system is related to blood flow, which contains oxygen.
The answer is through facilitated diffusion. It is then called as the transport of substances in a biological membrane from a higher concentration to a lower concentration area though carrier proteins. Hope this is the right answer and would be of help.
Answer:
I think the answer is B.
Explanation:
I think this because they have these variations to better adapt to conditions in their environments.
