| A | B |
|---|
| prokaryote | An organism that lacks a true nucleus in the cell. |
| eukaryote | An organism with cells that contain defined nuclei. |
| virus | Any of the small particles that invade and then replicate inside a living cell. |
| bacteria | Prokaryotes whose genetic material is not contained in a nucleus. |
| host | An organism that provides a source of energy for a virus or another organism to live. |
| parasite | An organism that lives on or in a host and causes harm to the host. |
| autotroph | An organism that produces its own food. |
| heterotroph | An organism that cannot make its own food. |
