Which of the following is not a main component of an ecosystem?
A. Food chains and webs
B. Physical surroundings, such as rocks, soil and water
C. Living organisms
D. Living and non-living factors that make up the environment.

a. by using fur or clothes to trap heat energy near the body

sorry to break it to ya but no one can answer your question it's just

jk but i am serious about the part that most people cant answer it beacuse you did not mention the section you are talking about. but it would if you added some detail and were a bit more specific.

i think the answer is a.keratin is the pigment responsible for skin color.