Across
- 4. stimulate the immune system to increase the production of antibodies
- 5. usually contagious and passed on to other animals
- 7. live on and in the bodies of animals
- 9. produce a certain type of white blood cell called antibodies
- 12. chemical released by lymphocytes
- 14. carry oxygen and other nutrients to other cells in the body
- 15. builds up over time
Down
- 1. animal is born with it
- 2. more difficult to treat than bacterial diseases
- 3. shaped in a spiral or corkscrew
- 6. circulate through the body to get rid of dead cells
- 8. cannot be spread through contact with other animals
- 10. a poison that destroys cells
- 11. a condition that causes the systems of an animal to not function properly
- 13. type of white blood cell that intercept and destroys pathogens