The answer is C. influenza, chicken pox, and colds because influenza, chicken pox, and colds (called rhinovirus) are all caused by viruses. Food poisoning is not a virus, athlete's foot is a fungal infection, and strep throat is a bacterial infection.
Cell structure over time is known as a free radical
Well, this is an opinion based question so it could go either way. I think it’s difficult because like anything, s*x can be an addiction. Though there is therapy, getting someone to do the act can be cheaper & easier.