412 BENEFICIAL ACTIVITIES OF BACTERIA 



C. Material produced. 



D. Commercial use of material produced. 



2. Make a library report on the tanning of leather. 



3. What is meant by soil exhaustion and soil renewal? 



4. What is the importance of the decay process to agriculture ? 



5. Explain nitrification in detail. 



6. Discuss denitrification. 



7. Discuss nitrogen-fixation. Give three different ways of fixing 

 nitrogen. 



8. What is the importance of rotating crops ? Give at least four 

 reasons for rotating crops. 



9. Mention four different facts that must be considered in culti- 

 vating soil. 



10. Make out an original carbon and nitrogen cycle. 



1 1 . Do farmers have scientific knowledge about bacteria or do they 

 depend upon their experience or on hearsay in caring for the soil ? 



12. Does the government make any effort to give farmers scientific 

 instruction in soil and crop improvement? 



13. Discuss a balanced aquarium. 



Supplementary Readings 



Gager, C. S., General Botany (P. Blakiston's Son & Co.). 

 Greaves, J. E. & E. O., Elementari/ Barferiohgj/ (W. B. Saunders Co.). 

 Holman, R. M., & Bobbins, W. W. A Textbook of General Botany (John 

 Wiley & Sons, Inc.). 



