1. What is the role of saliva in the digestion of food?

2. Describe double circulation in human beings. Why is it necessary?

3. How do guard cells regulate opening and closing of stomatal pores?

4. What is the significance of emulsification of fats?

5. What is the advantage of having four chambered heart?

6. How do carbohydrates, proteins and fats get digested in human beings?

7. Describe the process of urine formation in kidneys?

8. Describe the flow of blood through the heart of human being?

9. What criteria do we use to decide whether something is alive?

10.What is the role of acid in our stomach?

11. How are the lungs designed in human beings to maximise the area for exchange of gases?

12. Describe the structure and functioning of nephrons?

13. What would be the consequence of a deficiency of haemoglobin in our body ?

14. State the function of epiglottis?

15. Why does absorption of digested food occur mainly in the small intestine?

16. Give the role of liver in the human beings?

17. Describe three different waste products  formed in the human body?

18. One of your friends has been diagnosed with kidney stones .

(a). What are kidney stones? How are they formed?

(b). How do they affect our body?

19. Make the following diagram and label them. 1 Section of kidney 2 Process of ultrafiltration?

20. Draw a  label diagram of the human excretory system?