I think the answer is skin. Skin contains sweat glands which secrete a fluid waste called sweat or perspiration; nonetheless, its primary functions are temperature control and release of pheromone. Its role as a part of the excretory is therefore minimal. Additionally, sweating also maintains the levels of salt in the body.
I'm not too sure which one of these two but its either A or C
The nutrients that coats your nerves is something called myelin. Those like vitamin B and D can help out myelin sheath.
A homologous<span> structure is an organ, system, or body part that shares a common ancestry in multiple organisms. So the Structure is said to be C) Homologous. Hope this Helps</span>
