The term community refers to association or assembly of two or more different species population at the same geographical region and at a particular point of time. Community is a level in the organization of an ecosystem. In simpler terms, individuals create population, populations create community, communities create ecosystem, ecosystems create biome and biomes create biosphere. An ecosystem is composed of community (the biotic component) living in conjunction with the abiotic components such as soil, climate, water, etc.
The terms interact or interactions refer to relationship between different species and communities. Interactions include competition, predation, parasitism, mutualism, commenalism, etc. For example, species can compete with each other for limited resources, such as food or land, etc. and this interaction will influence the population size, species distribution, etc. Similarly, predator-prey interactions results in control of both populations.
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