Answered

An organism that lives in or on another organism, often with harmful side effects-but without benefits is a?

Answer :

This organism would be considered or called a Parasite
debmagnani

Answer:

Parasite

Explanation:

Parasitism is an interspecific ecological relationship (occurs between different species) where one species, called a parasite, feeds at the expense of another species, called a host, causing damage to it.