Across
- 3. clot the blood at the site of injury
- 6. di oxide toxic waste of respiration
- 8. gas needed for respiration
- 9. section sof chromosomes
- 12. molecules that make up structures like muscles.
- 14. carry pure blood from heart to body
- 15. structures that open and close between heart chambers
Down
- 1. respiration takes place
- 2. carry impure blood to heart from body
- 4. contain vocal cords
- 5. one of four nitrogenous bases of DNA
- 7. versions of genes
- 10. divides left and right parts of heart
- 11. substances that cause change in DNA
- 13. bones that surround and protect lungs