Across
- 3. provides immunity to an infectious disease
- 4. simple cells that do not have a true nucleus
- 7. changes in a species over several generations
- 10. any of the specialized structures within a cell
- 12. send signals to coordinate biological processes
- 13. when events cause changes in a population
- 15. gives physical evidence of ancient life
- 16. units that make up DNA and RNA
Down
- 1. the variety of life in the world or ecosystem
- 2. a virus that infects a bacterium and reproduces
- 5. natural ability of an organism to repel attack
- 6. the semifluid substance inside of a cell
- 8. all the organisms of the same group or species
- 9. infected by or is fed upon by a parasite
- 11. nucleic acid used in making proteins
- 14. infectious particle that needs a host cell
- 17. contains the genetic instructions of life