Describe the important steps of working sewage recycling plant...???

Plzzz hurry im being timed ! humans, like other organisms, require energy for growth and repair. when cells create atp for energy, carbon dioxide is produced as a waste product. how does the body respond to this process in order to maintain homeostasis? a. the digestive and respiratory systems interact to move carbon dioxide to the lower intestine, where it is transformed into methane. b. the circulatory and digestive systems interact to move carbon dioxide to the stomach, where it to break down food. c. the nervous and urinary systems interact to move carbon dioxide to the kidneys, where it is absorbed into the bloodstream. d. the circulatory and respiratory systems interact to transport carbon dioxide to the lungs, where it is expelled from the body.

In many humans, exposing the skin to sunlight over prolonged periods of time results in the production of more pigment by the skin cells (tanning). this change in skin color provides evidence that -

What is usually (but not always) related to the metabolic processes of living organisms in its organic form?