Which statement is accurate about evolution?
evolution maintains the genetic similarity of a population.
mutations are generally harmful.
natural selection eliminates odd individuals.
natural selection changes the genetic makeup of a population

Natural selection changes the genetic makeup of a population

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. 

The answer would be abrasion.

Cells of an organism tell each other when predators are near.