Predator

A. the study of interactions of living organisms with one another and thier environment.
B. A relationship between two species in which both species benefit.
C. An organism that kills and eats another for food.
D. A relationship between two species in which one species, the parasite, benefits from the other species, the host, which is harmed.

C. An organism that kills and eats another for food is known as a predator.