Answer:
E.
Explanation:
Im sorry if it's wrong but that's what I would go with
It is system because bone nucleus and all the rest you put down are all a system structure in the body
<span>the portion of an antigen that binds covalently to an antibody</span>
The three types of chemical bonds are Ionic, Covalent, and Metallic
There is a huge difference between<span> bioitic and </span>abiotic<span>. </span>Biotic<span> means living ("bio") and </span>abiotic<span>, as stated by ayl0124, is the opposite, meaning nonliving. </span>Biotic factors<span>are part of the ecosystem. Some of these include plants and bacteria.</span>