| A | B |
|---|
| cell | the smallest unit of living matter |
| extinct | died out; as when a species no longer exists on Earth |
| organism | a living thing that carries out five basic life functions |
| protist | typically a one-celled organism that lives in moist places |
| species | the smallest group into which an organism is classified |
| trait | a characteristic of a living thing |
| function | a natural action |
| energy | what an organism needs to perform an action |
| human actions | can cause a species to become extinct |
| science | knowledge about the natural world that is based on facts learned through experiments and observation |
