Which of the following best defines an organism's niche?

An organism's niche is best defined as its role and position within its environment. This concept encompasses not only the physical space the organism occupies but also how it interacts with other organisms and its environment in terms of resources, habitat use, and relationships with other species, including predation, competition, and mutualism.

The niche includes the full range of biotic and abiotic factors an organism interacts with, as well as its behavior, diet, and the impact it has within its ecosystem. This comprehensive view allows ecologists to understand how different species coexist and what roles they play in maintaining ecosystem balance.

While the physical habitat is an important aspect of a niche, it does not encompass the entire ecological role that an organism plays. Similarly, species interactions and reproductive strategies are components of an organism's ecology but do not alone define the niche concept, which integrates various aspects of how an organism lives, survives, and contributes to its ecosystem as a whole.