Suppose a salamander and a small tree are engaged in an ecological relationship in which only the salamander benefits, but the tree is not harmed. This relationship is a , and for the tree, it is .

This relationship is a COMMENSALISM RELATIONSHIP, and for the tree, it is FACULTATIVE.

Explanation:

Commensalism is a type of heterotrophic mode of nutrition is which two organisms of different species live together where one species benefits while the other species is not affected The ecological relationship between the salamander and the tree is a good example where the tree provides shelter for the salamander( especially the terrestrial types) and is unharmed by the organism.

The tree is said to be facultative because it can survive without the presence of the salamander, meaning that their relationship is not an obligate type rather it's by choice.