1. What is the largest mammal in the world?

2. What is the largest internal organ in the human body?

3. What organ is primarily responsible for filtering blood?

4. What is the hardest substance produced by the human body?

5. Why do identical twins have different fingerprints?

6. What is the largest organ of the human body?

7. What percentage of the body's total energy consumption is used by the brain?

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

9. Which bone is the longest and strongest in the human body?

10. Which branch of the nervous system is responsible for the 'fight or flight' response?

11. Which region of the spine is located in the neck?

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

13. From which parent do humans inherit nearly all of their mitochondrial DNA?

14. What is the name of the active growth phase of a hair follicle?

15. What is the term for the widening of blood vessels to increase blood flow to the skin and release heat?

16. Which part of the human eye is unique for having no blood vessels and receiving oxygen directly from the air?

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

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

19. Which part of the brain is primarily responsible for fine-tuning motor movements and maintaining balance?

20. What is the primary evolutionary purpose of the human blink reflex triggered by the eyelashes?