Here’s what I found on quizlet
<span> All the millions of different proteins in living things are formed by the bonding of only </span>20 amino acids<span> to make up long polymer chains.</span>
As epithelial makes the outer covering of all the organs and skin is also made of epithelial...so to be sure that it does not get depleted or destroyed due to friction and other external cause ...it should be highly generative !
I would have to say Proteins, lipids, and carbohydrates. Carbohydrates being the first energy source, lipids second and lasting the longest, and proteins the third and final source. although you did not give the full question, so i do not know if i can be completely sure.
