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Biological levels of organization (smallest to biggest)

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molecules
group of atoms, smallest unit of chemical compounds (1)
cells
smallest functional unit of life (2)
Groups of cells
tissues, organs, and organ systems (3)
organism
individual living thing (4)
population
group of organisms of one type that live in the same area (5)
community
populations that live together in a defined area (6)
ecosystem
community and its nonliving surrounding (7)
biosphere
the part of the earth that contains all ecosystems (8)