A collection of population of all living organisms that exist in a habitat is referred to as

1. Analyze the question The question asks for the term describing all the populations of living organisms (plants, animals, microbes) found together in a habitat. The key phrase is "collection of populations of all living organisms."

2. Explain the concepts Ecology has a hierarchy of terms:

• Population: a group of organisms of the same species living in an area (e.g. all the tilapia in a pond).
• Community: all the populations of different species living and interacting in a habitat (plants, animals, microbes together).
• Ecosystem: the community plus its non-living (abiotic) environment, such as soil, water, light, temperature, and the interactions between them.
• Niche: the role or functional position of an organism in its habitat (what it eats, where it lives, how it interacts).
• Environment: the total surroundings, both living (biotic) and non-living (abiotic).

3. Solve step by step

• The question mentions only living organisms, with no non-living components. That rules out ecosystem (B) and environment (D), which both include abiotic factors.
• It talks about a collection of populations, not the role of one organism. That rules out niche (A).
• A collection of populations of different living organisms in one habitat is a community.

4. Answer The correct option is C. community.

5. Exam tip Remember the build-up: Population → Community → Ecosystem. If the question says "living things only," think community. If it adds non-living factors (soil, water, climate), think ecosystem.