Final answer:
An ecosystem consists of individuals, populations, and communities, which are defined as single organisms, groups of individuals of the same species, and two or more interacting populations of different species, respectively.
Step-by-step explanation:
An ecosystem consists of individuals, populations, and communities. An individual is a single organism of a particular species. Two or more interacting populations of a different species constitute a community. A population is a group of individuals of the same species living in the same region.
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