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group of atoms, smallest unit of chemical compounds (1)


smallest functional unit of life (2)

Groups of cells

tissues, organs, and organ systems (3)


individual living thing (4)


group of organisms of one type that live in the same area (5)


populations that live together in a defined area (6)


community and its nonliving surrounding (7)


the part of the earth that contains all ecosystems (8)

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