Question:

Which one of the following is most appropriately defined?

Host is an organism which provides food to another organism.

Predator is an organism that catches and kills other organism for food.

Parasite is an organism which always lives inside the body of other organism and may kill it.

Amensalism is a relationship in which one species is benefited whereas the other is unaffected.

Solution:

Predator is an organism that hunts, catches, kills, and eats other animals. Parasitism is a type of symbiosis where one organism (the parasite) benefits and the other (the host) is harmed. A host is an organism that harbors a parasite, or a mutual or commensal symbiont, providing nourishment and shelter. Amensalism is an association between organisms of two different species in which one is inhibited or destroyed and the other is unaffected.