Answer:
Option C
Explanation:
Option A is incorrect as mutations may be detrimental to the organism and are not always beneficial. Option B is incorrect as there are instances where mutations may enable organisms to be better adapted to the environment. Option D is incorrect as genotypes are not selected for or selected against by environmental pressures, it is only the phenotype (exhibitable/ visible traits) that can be selected for or against, hence option C is the answer.
It has a lot of advantages as well as disadvantages; but they prevent or suppress the entry of pathogens; colonies produced by some organisms of normal flora have a harmful effect on the pathogens; endotoxins liberated by normal flora may help the defense mechanism of the body. (Make me the brainless please)