Question: How do the circulatory system and the respiratory system depend on one another?

  Options: 
 A. Oxygen collected by the respiratory system is carried throughout the body by the circulatory system.
 B. Solid wastes collected by the circulatory system are carried throughout the body by the respiratory system.
 C. Nutrients collected by the respiratory system are carried throughout the body by the circulatory system.
 D. Carbon dioxide collected by the circulatory system is carried throughout the body by the respiratory system.
Answer: A