Appetite is not linked to hunger since appetite is the activity and drive in order to eat whereas hunger is the physical and mental state in which a person needs to eat.
Also appetite is linked to many unhealthy behaviors that can result to other symptoms of eating disorders which causes deletrious effects on one's mental and biological state.
The skeletal system protects the brain and other important organs
I mean they are necessary for some people..
Not sure about eating them
<span>The common cold, the flu, food poisoning, and toothaches all stem from pathogens. Pathogens are infectious agent that causes disease or illness to its host. The term is often used for agents that disrupt the normal physiology of a multicellular plant or animal, like the human.</span>