Which statement best explains how organ systems work together to remove wastes?

a. the nervous system controls the movement of food through the
digestive system.

b. the circulatory system carries carbon dioxide away from cells, and
the respiratory system removes it from the body.

c. the respiratory system takes in oxygen, and the circulatory system
delivers it to body cells.

d. the digestive system takes in food and breaks it down into nutrients, and the circulatory system delivers them to body cells.