A biologist identifies an organism that lives in the gills of a fish and consumes the fish’s blood. What type of relationship do the organism and fish have?
A parasitic relationship is a type of relationship in which one organism, the parasite, lives off of another organism, the host, harming it and possibly causing death.
The organism that is harming the other one is called a parasite. Examples of Parasitism includes fleas or ticks that live on dogs and cats are parasites.
In this case; the organism that lives in the gills of a fish consuming fish's blood is the parasite, while fish is the host.