Predation and parasitism are distinct from one another because predation results in the instantaneous death of the prey, while parasitism does not cause the host organism to perish. While predators feed on others, parasites ingest nutrients from their hosts and other species. Predation is a relationship in which members of one species consume members of another species. A predator-prey relationship keeps the populations of both species in balance. Parasitism is a relationship between two species in which one of them benefitted and the other species is harmed. Symbiosis is a close relationship between two species in which usually both get benefits from each other. There are four main types of predator-prey relationships: carnivory, herbivory, parasitism, and mutualism. Carnivory occurs when one animal eats another, and herbivory occurs when animals eat plants or algae. Parasitism is a predator-prey relationship in which the predator does not kill its prey.In the predator prey relationship, one species is feeding on the other species. The prey species is the animal being fed on, and the predator is the animal being fed. The predator prey relationship develops over time as many generations of each species interact. Symbiosis is defined as a close, prolonged association between two or more different biological species. This relationship can be symbioti, where both parties involved benefit from the interaction, or it can be parasitic, where one party benefits while the other is harmed. A symbiotic relationship in which a symbiont lives all or part of its life in or on a living host, usually benefiting while harming the host in some way and usually having a higher reproductive potential than the host.