Compositional layers are determined by their components, while mechanical layers are determined by their physical properties.
Answer:
keratin
Your nails are made of keratin
Keratin is a type of protein that forms the cells that make up the tissue in nails and other parts of your body.
Explanation:
I believe that the answer is E
Well its a little deeper than that. The oxygen transport is made through Hemoglobin (red blood cells) which is pumped from the heart
