Answer:
The correct answer is - A. niche.
Explanation:
A niche can be understood as the functional role or the employment of an individual organism or population fits in an ecosystem or community. It is the way an organism to behave or interact with the ecosystem.
In this case, the insect species obtain its food from utilizing the branch of the willow tree is explains its functional role and the way it interacts with other factors of the ecosystem.
