Which statement best defines a niche?

• A. The physical area where an organism lives.
• B. The rainfall and climate of a habitat.
• C. A group of organisms living together.
• D. An organism's role in the ecosystem and its resource use and environmental requirements.

Answer: (D)

A niche is an organism’s role in its ecosystem, including how it obtains resources, how it interacts with other organisms, and the environmental conditions it needs to survive. This definition captures how the organism fits into its community, not just where it lives or the weather it experiences. So the statement that mentions an organism’s role, its use of resources, and its environmental requirements best defines a niche. In contrast, a habitat describes the physical place, climate describes weather patterns, and a group of organisms living together refers to a population or community, not the organism’s specific role.