Across
- 1. The body's ability to resist harmful substances
- 5. preparations that are composed of dead or weakened viruses
- 6. When the body remembers the germ and knows how to fight it
- 8. Proteins released into the blood to neutralize or destroy the germs
- 9. a disease that occurs in the body
Down
- 2. a disease you can catch
- 3. single or multiple celled organisms that have no roots or stems
- 4. A tiny single cell organism
- 7. non living and need a host to survive