Across
- 3. spread of infection within a country
- 5. various types of cell involved in defense against disease
- 7. only visible with a microscope
- 12. infection spread across countries
- 13. a group of single cell living things
Down
- 1. disease picked up from other organisms
- 2. a breakdown of the body's ability to fight disease
- 4. small living things
- 6. type of virus that can lead to AIDS
- 8. the ability to fight off a disease
- 9. an individual living thing
- 10. an illness affecting part of or all of an organism
- 11. micro-organism that causes infection