Mrsa is meticillin-resistant staphylococcus aureus, a strain of bacterium. meticillin is a similar substance to penicillin, used to treat bacterial infections.

name the type of substance meticillin is, and explain your answer

the answer to your question is tooth decay.

idk about that one.

the right option is; decreased genetic variation  

decreased genetic variation describes the effect of this environmental change.

genetic variation is the naturally occurring genetic diversities or differences between organisms of the same species in a population. genetic variation allows the survival and adaptability of a species when they encounter changing environmental conditions. when an endangered species reduces, it loses genetic variation which may not be restored even if the species rebound and will only be recovered through the gradual collection of mutations over many years.