
Blood is vital to most animals. In mammals it transports oxygen and food, carries away waste, and contains the white cells that attack invading microbes. Playing a central role in life, it has had profound cultural and historical significance and plays an important role in religious...

Blood is vital to most animals. In mammals it transports oxygen and food, carries away waste, and contains the white cells that attack invading microbes. Playing a central role in life, it has had profound cultural and historical significance and plays an important role in religious...