Me what is the main function of the circulatory system? a. to deliver oxygen and nutrients to cells throughout the body b. to provide all major organs with carbon dioxide c. to remove waste from the body d. to digest food

Ok  the main function of the circulatory system is to deliver oxegen and nutrients to the body

The answer is definately A. There is not really an explanation that could be given for this as it is something one just has to know. Just think of it as the word circulates. The circulatory system circulates or moves oxygen and nutrients to cells throughout the body. So delivery is the only one that makes sense.