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

A) mutualism

B) parasitism

C) commensalism

D) facilitation

B) parasitism

Explanation:

Parasitism is a kind of symbiosis association, a close and consistent long-term biological interaction between a parasite and its host. Parasitism is a relationship between species, where one organism, (the parasite) lives on or in another organism, (the host), causing some harm to the host. Parasites feed on living hosts, unlike commensalism and mutualism, the parasitic relationship harms the host, either feeding on it or, as in the situation of intestinal parasites, consuming some of its food.

Parasites reduce the fitness of the host by general or specialised pathology, from parasitic castration to modification of host behaviour. The opposite is true for parasites as the increase their own fitness by exploiting hosts for resources necessary for their survival, in particular by feeding on them.

In the case of dwarf mistletoes and vasular tissues of the trees. The dwarf mistletoes derived it necessary nutrients and other resources necessary for survival, hence endangering the vascular tissues of the trees with limited nutients to carry out its life processes.