Biology Exam Extra Credit Crossword

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Across
  1. 2. Chemical messenger in the body.
  2. 3. Neural pathway for a reflex.
  3. 6. Loop of _____. Structure in the nephron that concentrates urine.
  4. 9. A cell that forms new bone tissue.
  5. 12. The process of returning useful substances to the blood.
  6. 13. A pigment that gives color to skin and hair.
  7. 14. The layer of skin beneath the epidermis.
  8. 17. A flexible connective tissue that cushions joints.
  9. 18. How energy in food is measured.
  10. 19. Colored part of the eye.
Down
  1. 1. A band of tissue that connects muscle to bone.
  2. 2. The maintenance of a stable internal environment.
  3. 4. A mixture of partially digested food and stomach secretions.
  4. 5. The hormone that triggers childbirth.
  5. 7. Macronutrients that regulate body processes.
  6. 8. A device that regulates the heartbeat.
  7. 10. Part of a neuron that receives signals.
  8. 11. The most important nutrient.
  9. 15. The muscular tissue of the heart.
  10. 16. A macronutrient that provides energy and insulation.