Blood is the red fluid that flows inside the blood vessels and is composed of cells and fluid.... The cells are red blood cells, white blood cells and platelets, and the fluid is plasma, and blood is one of the most important vital fluids in the human body because of its vital functions. Important, such as transporting oxygen and nutrients to the different cells of the body, and the blood is about 8% of the body weight, and the normal rate of blood ranges from 4 to 6 liters in a person of average weight, and losing 1 liter of blood during donation does not have a severe impact on the body as Blood quickly forms and returns to its volume again within 24 to 48 hours Blood analyzes are usually performed on blood taken from veins or arteries by means of a thin capillary puncture
