Please help me with this.

why is it that blood pump away from the heart under pressure?

why is it necessary for blood to be oxygenated before pumped to the cells?

Please this question is under the topic circulatory system.

not sure about the first one..

the second one is that oxygenated blood obviously carries oxygen with it. Why? It is necessary to have oxygen so that the cells will have oxygen delivered to them. Without oxygen, the cells will not function properly and can start to deteriorate and die. Thus, when blood is pumped to the cells it must be oxygenated.