1. What is the rarest blood type?

2. Which type of photoreceptor cells in the human eye are primarily responsible for color vision?

3. Why do adults have fewer bones than newborn babies?

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

5. Which type of sweat gland is found all over the body and is primarily responsible for temperature regulation?

6. Besides fingerprints, which of the following is unique to every individual and can be used for biometric identification?

7. Which human cell is large enough to be seen with the naked eye?

8. Which muscle in the human body is considered the strongest based on its weight and ability to exert force?

9. What is the name of the structural protein that is the primary component of human hair and nails?

10. Which part of the central nervous system processes a reflex action like the 'knee-jerk' or pulling away from heat?

11. Where is the vestibular system, which controls balance and spatial orientation, located?

12. What is the snail-shaped structure in the inner ear responsible for hearing?

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

14. What is the name of the wave-like muscle contractions that move food through the digestive system?

15. What is the name of the muscle that controls the passage of food from the stomach to the small intestine?

16. What is the primary purpose of the blood-aqueous barrier in the human eye?

17. What is the function of the Eustachian tube in the human ear?

18. What is the anatomical name for the 'white of the eye'?

19. Why is the blood-testis barrier necessary for male fertility?

20. What two gases are exchanged across the blood-air barrier in the lungs?