The <span>amount of food, habitat, water, and other necessities available in the </span>environment<span>.</span>
This is possible because proteins are created from different combinations of amino-acids. While we only have 20 different kinds of aminoacids, these 20 kinds can create thousands of combinations that we can observe in our bodies and bodies of other mammals as well as other organisms.
The answer is....... (drumroll)........ lipids!