Which of the following statements about secondary succession is true? a. Secondary succession occurs in ecosystems that have no vegetation. B. Secondary succession affects ecosystems that are already established. C. Ecosystems require pioneer species to undergo secondary succession. D. Secondary succession can occur in areas without soil. Please select the best answer from the choices provided A B C D.

bacteria could be both, harmful and to us. harmful bacteria could make us sick and probably even by getting the chances of getting a disease, but good bacteria fight it off with your immune system. there is always bacteria everywhere we go. we need to make sure to wash our hands after using the restroom, before eating, after eating, after petting an animal too. so you see, bacteria is everywhere and is harmful or . i hope this . : ) : ) : )

answer; three;