| A | B |
|---|
| oxygen | a part of the air that most plants and animals need to live. |
| organism | Any living thing that carries out the five basic life functions on its own. |
| cell | the smallest unit of living matter. Also known as "the legos of life" |
| tissue | A group of cells that work together to carry out a job. example: skin |
| organ | a group of tissues that work together to do a certain job. example: heart, lungs, etc. |
| organ system | A group of organs that work together to carry out life functions. |
| kingdom | The largest group into which organisms can be classified. |
| trait | A characteristic of a living thing. |
| genus | A group made up of two or more very similar species. |
| species | The smallest group into which an organism is classified. |
| fossil | Any evidence of an organism that lived in the past. |
| embryo | A developing organism that results from fertilization. |
| extinct | An organism that no longer exists. |
