Answer:
we cant we need the answers that apply to it
Explanation:
Oxygen is non metal meaning they are negative
One major function of the endomembrane system is transporting substances in and out of a cell.
A relatively small blood pressure gradient is generally insufficient to move blood through the veins under given conditions, thus venous return must be facilitated by valves within veins and two "pumps." ... As skeletal muscles contract, veins are squeezed to help propel the blood toward the heart.
