An association between living organisms in which one lives on and feeds at the expense of the other organism is known as

An association between living organisms in which one lives on and feeds at the expense of the other organism is known as parasitism. In parasitism, the parasite benefits from the relationship by deriving nutrients from the host, while the host is harmed by the relationship. Parasites may live on the surface of the host's body or inside its tissues, and can cause a range of negative effects, from mild irritation to severe disease or even death. Parasitism is a common type of interaction in nature, with many species of animals and plants acting as both parasites and hosts. For example, ticks and fleas are parasites that feed on the blood of mammals, while mistletoe is a parasitic plant that feeds on the sap of trees. Parasitism is different from predation, where one organism kills and eats another for food. In parasitism, the parasite feeds on the host's tissues, but typically does not kill the host outright.