The circulatory system is the heart and all the blood vessels. Find out more with Bitesize. For students between the ages of 11 and 14. ... Humans have a double circulatory system, ...

Evolution of circulatory system. Trend for separation of oxygenated and deoxygenated blood. These changes resulted from the changes from gill to lung respiration, change from aquatic to terrestrial ...

Your circulatory or cardiovascular system serves a vital function by delivering oxygen and nutrients to all the organs and tissues of your body. Learn more about how the circulatory system works ...

Evolution of circulatory system. Trend for separation of oxygenated and deoxygenated blood. These changes resulted from the changes from gill to lung respiration, change from aquatic to terrestrial ...