What is a biological indicator?

How are mutations continually being generated in a population (what are some of the causes of mutatuions? ) explain

Select the true statements about eubacteria. most live as decomposers and heterotrophs. most only thrive in a narrow range of environments. certain eubacteria are responsible for food poisoning. eubacteria thrive in extreme environments.

Ialready know the answers to these questions and they are on the attachment. but i just need to know why that answer is the correct one. plz asap! this is for a report that i need to email by 10!