Which term refers to the physical environment where an organism lives?

• A. Niche
• B. Habitat
• C. Parasitism
• D. Population

Answer: (B)

The main idea is that habitat names the physical environment where an organism lives. A habitat includes the abiotic conditions like depth, temperature, salinity, light levels, substrate, and water movement, as well as the presence of shelter and available food in that area. In the ocean, examples include coral reefs, seagrass beds, and rocky shores—each defined by its specific physical characteristics that let organisms survive there. This is different from a niche, which describes the role the organism plays in the ecosystem—how it makes a living, what resources it uses, and how it interacts with other organisms. Parasitism is a type of ecological relationship, and population refers to how many individuals of a species are in a given area. So the term that refers to the physical environment where an organism lives is habitat.