When the arteries reach cells, they divide into smaller blood vessels called:
(a) What are the upper parts of the heart called ? (b) What are the lower parts of the heart called ? (c) What is the name of blood vessels which connect arteries to veins ? (d) (i) Which side of the heart pumps blood into the lungs ? (ii) Which side of the heart pumps blood into entire body (except the lungs) ?
Artery gets divided into smaller vessels and the smallest vessels have walls which are one-cell thick. These smallest vessels are called __.