Blood is a specific bodily fluid which supplies essential substances and nutrients like sugar, oxygen, and hormones to the human body cells. It also collects waste from those cells to the kidneys, which is eventually flushed out from the body in form of in urine, faeces, sweat, and lungs (carbon dioxide). Blood also contains clotting agents to prevent bleeding process during accidents.
Blood accounts for about 7% of the total human body weight. An average adult has blood volume of about roughly 5 litres. Blood is composed of plasma, red blood corpuscles, white blood corpuscles and platelets. In terms of volume, the red blood cells constitute roughly 45% of whole blood, plasma cells of about 54.3%, and the white cells to about 0.7%.