1. How many teeth does a typical adult human have?

2. What part of the human eye controls the amount of light entering?

3. What type of blood cells help fight infection?

4. What gas do humans exhale when breathing?

5. What organ is primarily responsible for filtering blood?

6. Which animal is known as the “ship of the desert”?

7. What is the only internal human organ capable of regenerating itself completely from as little as 25% of its original tissue?

8. Why do identical twins have different fingerprints?

9. What is the name of the fatty insulating layer that allows nerve impulses to travel faster?

10. If uncoiled, the DNA from all the cells in a single human body would reach approximately how far?

11. Which part of the brain is primarily responsible for regulating body temperature, hunger, and thirst?

12. What is the primary role of the 'red pulp' within the spleen?

13. Which antibacterial enzyme is found in human tears and helps protect the eyes from infection?

14. Where in the human body are the menisci located?

15. Which cranial nerve is the primary component of the parasympathetic nervous system?

16. What is the name of the fatty insulation that speeds up nerve impulses?

17. Which hormone, produced by the kidneys, stimulates the production of red blood cells?

18. Which bone in the human body is unique because it does not connect to any other bone?

19. How often does the human body replace the entire lining of the stomach?

20. What is the term for the body's ability to sense its own position and movement without using sight?