| A | B |
|---|
| biosphere | The part of the Earth inhabited by living organisms; includes both the living and nonliving components |
| ecosystem | A community together with its nonliving surroundings |
| community | Two or more populations of different species living and interacting in the same area |
| population | members of one species inhabiting the same area |
| species | very similar, potentially interbreeding organisms |
| multicellular organism | an individual living thing comprised of many cells |
| organ system | two or more organs working together in the execution of a specific bodily function |
| organ | a structure with in an organsim ususally composed of several tissue types that form a functional unit |
| tissue | a group of similar cells that perform a specific function |
| cell | the smallest unit of life |
| organelle | a structure within a cell that performs a specific function |
| molecule | a combination of atoms |
| atom | the smallest particle of an element that retains the properties of that element |
| subatomic particle | particules that make up an atom |
