All 12 with their definitions:
BiosphereInteraction between organisms and their environment, which includes both biotic and abiotic factors.
CommunityAll organisms in a particular area.
PopulationAll individuals of a particular species in a particular area.
OrganismAn individual.
Organ systemA group of organs that work together to perform a certain task.
OrganTissues that work in unison to carry out a specific set of functions.
TissueA group of cells with the same structure and function.
CellThe basic biological unit of life in all organisms. The smallest autonomous self-replicating unit.
OrganelleAn organized differentiated structure with a cell that performs a specific function.
MoleculeTwo or more atoms combined.
