How
does human evolution or natural selection relate to the susceptibility of disease?

Human evolution is similar to every evolution in the animal and plant kingdom. Forced by the environment both internal and external forces, animals adapted to the extreme conditions they were put in. As humans evovled, bacteria and other microorganisms also evolved to better attack and obtain food from other organisms including mankind. 

Only algae, oak trees, and bermuda grass produce atp by photosynthesis i am almost positive