Answer: Differentiation allowed the brain and kidney cells to become specialized for the structures and functions they possess.
Explanation:
Some have been noted to live as long as 6 days without there head.
Answer:
It is necessary to separate oxygenated and deoxygenated blood separate in mammals and birds to maintain their body temperature. Also, if they both are mixed, the blood will get impure and it would be difficult for the heart to supply impure blood. We also can't live with impure blood so we most probably will die.
