Answer: Orchids are commensal in nature.
Strangler figs are parasitic in nature.
Explanation:
Symbiotic relationships can be define as interactions which occur in between the two distinct species. Such interactions can be either harmful or beneficial for the associating members.
Commensalism is a symbiotic relationship in which one species receives the benefit and the other species receives neither harm nor benefit. Parasitism is a symbiotic relationship in which one species derives the benefit at an expense of the other species.
According to the situation given the Strangler figs absorb the nutrition from the host trees and they leave the host trees devoid of sunlight and nutrition. Here, Strangler figs are only receiving the benefit but the host trees are getting exploited therefore, it is an example of parasitism.
Orchids also live in symbiotic relationship with the tropical trees. But they receive sunlight and moisture from the surrounding this way the orchids are not causing any harm to the tropical trees. Therefore, it is an example of commensalism.