What are the two main parts of an organism's niche?

The idea of an organism’s niche encompasses the role it plays in its ecosystem, which includes both its habitat and its behavior. When we refer to "where it lives," we are identifying the specific environmental conditions and geographical area that the organism occupies, known as its habitat. On the other hand, "what it does" refers to the organism's activities—how it interacts with its environment, how it obtains food, and how it contributes to the ecosystem functions. This combination of habitat and behavior helps define the organism's ecological niche, illustrating its unique position within the ecological community.

While the other options might relate to different aspects of biological study, they do not encapsulate the full concept of a niche as effectively. Physical appearance and reproduction pertain more to the organism’s morphology and life cycle rather than its ecological role. Interactions with other species and the environment are certainly important, but without considering the specific habitat, they do not complete the picture of niche. Finally, population and geographic distribution are more about demographic aspects rather than the functional relationship an organism has with its environment. Thus, the definition of an organism's niche focuses specifically on its habitat and its role within that habitat.