The answer is B.
Animals do cellular respiration which requires the intake of oxygen and the output of carbon dioxide. In order for plants to do photosynthesis, they need carbon dioxide to be able to make oxygen for animals to breathe.
People who have darker skin have more melanin which is a black or dark brown pigment in the skin. When we are out in the sun our skin produces more melanin, which helps our skin be more resistant in the sun. This is why we tan.
Answer:
d is the answer for this question
