Corals feed off the byproducts of a microscopic algae living within their own tissue, called zooxanthellae. The photosynthetic activity of the algae is vital to the
survival of the coral animals, which use the energy to extract calcium from the
seawater and build their calcareous skeletons. The zooxanthellae are protected
by the hard coral and obtain plant nutrients from the coral. What type of relationship is this?

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; nociceptive pain;