who is this Justin Bieber??!
The correct option is C.
The heart is part of the cardiovascular system. The heart pump the blood round the body several times in a day. The blood is made up of several types of cells which carry out specific function in the body, these include the white blood cells which serves as soldiers of the body. The lymph refers to the fluid that circulate throughout the lymphatic system. Both the blood and the lymph are carried round the body by the cardiovascular system during the process of circulation.<span />
Important muscle electrical signals is the movement of charged material (ions) across cellular membranes in a limited area
