D. Organisms have cells with different shapes and functions.
Answer:
You mean How does the contractile vacuole in a single celled organism maintain homeostasis?
If that was it then It pumps water out of the cell
Explanation:
The artery does not carry oxygen depleted blood.
Quite the opposite, actually. Hope it helped!
B. population density.. I think....
Answer:There are two conditions that must be met for an object to be in equalibrium.
Explanation:1. The first condition is that the net force of the object must be zero for the object to in equalibrium.
2.If net force is zero then net force along any direction is zero.