Dwarf mistletoes are flowering plants that grow on certain trees in forests. They obtain nutrients and water from the vascular tissues of the trees. The trees derive no known benefits from the dwarf mistletoes. Which of the following best describes the interactions between dwarf mistletoes and trees?

A) competition

B) mutualism

C) commensalism

D) parasitism

E) facilitation

Answer: D - Parasitism

Explanation: Parasitism is an intimate and long-term impact or interaction that a couple of organisms living in the same habitat have on themselves between two distinct living beings, where one organism lives on another living being which gives it food, eater and shelter at the expense of the other organism.

The organism that lives in the host organism causes it some damage and gives no benefits at all. Also, the parasites are usually insignificant in size when compared to the organisms they live and feed on so they are able to survive in a large category of environmental situations. In this case, the dwarf mistletoes are the parasites while the trees are the hosts.