The answer would be B.) Sweat gland
It is carbon dioxide. Photosynthesis use carbon dioxide to produce oxygen.
Consuming enough protein is important because the broken down protein is used for energy. Consuming relatively high or excess protein is still safe and healthy but too much of it can be associated with different complications in the body.
Some of the problems associated with the excess protein are: (1) weight gain, (2) reduced liver and brain function, and (3) high cholesterol.