Which one of the following statements is correct about the human circulatory system ?
Option: 1 Blood transports only oxygen and not carbon dioxide.
Option: 2 Human heart has five chambers.
Option: 3 Valves ensure that the blood does not flow backwards.
Option: 4 Both oxygen-rich and oxygen-deficient blood gets mixed in the heart.
option (C) is the correct answer.
Valves ensure that the blood does not flow backwards.