1. If you lined up all the neurons in the brain end to end, they would stretch:

2. What percentage of our body energy is used to power the brain?

3. For what organ is dialysis used?

4. What is the main organ of the cardiovascular system?

5. What are the chambers of the heart called?

6. On average, how many times does the human heart beat each minute?

7. What is another word for the alimentary canal?

8. What is the part of the eye where the image must be focused?

9. Which of these are found in the eyes?