How does sexual reproduction increase the chance of genetic diversity

Which of the following is an example of this type of co-evolution

Which of the following is true of microbes? a. ninety-nine percent of all microbes are pathogenic.b. gene expression in bacteria is very similar to gene expression in humans, which facilitates the use of bacteria in recombinant biotechnology and gene therapy.c. all bacterial enzymes are harmful to humans and the environment.d. microbes create pollutants and toxins that harm the environment.

Why is excretion necessary to maintain homeostasis?