1. Do all cells use oxygen to produce energy?

2. Name one substance which is produced in anaerobic respiration by an organism but not in aerobic respiration.

3. Name one organism which can live without oxygen.

4. In which type of respiration, aerobic or anaerobic, more energy is released?


5. Name the substance whose build up in the muscles during vigorous physical exercise may cause cramps.

6. Which part of roots is involved in the exchange of respiratory gases ?

7. Name the process by which plant parts like roots, stems, and leaves get oxygen required for respiration.

8. Name the pores in a leaf through which respiratory exchange of gases takes place.


9. Name the areas in a woody stem through which respiratory exchange of gases takes place.

10. What is the name of the extensions of the epidermal cells of a root which help in respiration?

11. Out of photosynthesis and respiration in plants, which process occurs:

(a) All the time?


(b) Only at daytime?

12. Name the organs of breathing in fish.

13. Name an animal which absorbs oxygen through its moist skin.

14. Name an animal which depends on simple diffusion of gases for breathing.


15. Name two animals which breathe through gills.

16. The trachea divides into two tubes at its lower end. What is the name of these tubes?

17. Where does the blood absorb oxygen in the human body?

18. Name the red pigment which carries oxygen in blood.


19. Which gases are exchanged in your lungs?

20. Where in the lungs does gas exchange take place?

21. What is the name of tiny air-sacs at the end of smallest bronchioles in the lungs?

22. What is the other name of wind-pipe?


23. What organs are attached to the two bronchi?

24. In the lungs:

(a) What substance is taken into the body?

(b) What substance is removed from the body?

25. State whether the following statements are true or false:

(a) During respiration, the plants take C02 and release 02.

(b) Energy can be produced in cells without oxygen.

(c) Fish and earthworm exchange gases during respiration in the same way.

26. Fill in the following blanks with suitable words:

(a) The organs of respiration in man are the….

(b) The actual exchange of gases takes place in the lungs.

(c )………… in the lungs provide a very large surface area for gaseous exchange.

(d) Yeast undergoes…….. respiration whereas Amoeba undergoes……… respiration.

(e) Gills are the breathing organs in…..


1. No 2. Ethanol 5. Lactic acid 7. Diffusion 10. Root hair 11. (a) Respiration (b) Photosynthesis 17. Alveoli in lungs 24. (a) Oxygen (b) Carbon dioxide 25. (a) False (b )True (c) False 26. (a) lungs (b) alveoli (c) Alveoli (d) anaerobic; aerobic (e) fish