How does a vaccination to prevent a disease? it reduces the severity of symptoms to a disease. it generates a population of memory cells that speed up response to an actual infection. it generates a population of plasma cells that increase the concentration of antibody in the bloodstream. it establishes defenses that prevent a pathogen from returning to the body?

             Vaccine generates a population of plasma cells that increase the concentration of antibody in the bloodstream.
Explanation:
             Vaccines are inactive or non functional infectious agents enter into the body in order to generate antibody against such agents In future if virus or bacteria that is resemble to the structure of already injected agents attack on human body. The immune system get alert and antibody which are already produced attack on them and prevent them from causing disease.

It is evolution, because we all have some of the same traits like eye color or shape or ears.

Sorry  i don't understand can you rephrase that