1. The presence of the pigment __________, makes the green plants autotrophs.

2. On fresh weight basis, _________is the most abundant element in the plant body as well as other organisms.

3. Commercial cultivation of crops using hydroponics is known as ___________.

4. ______________ facilitates the translocation of carbohydrates (sugars and starches) and enhances the production of oils and fats.

5. The common symptom of nitrogen deficiency in plants is ____________.

6. The deficiency of _____________ causes the death of the stem and the root species. 

7. _________is a constituent of certain electron carrier proteins such as ferredoxin and cytochromes.

8. Yellowish edges appear in leaves deficient in _________________.Magnesium

9. Manganese is absorbed from the soil in the form of __________ions.

10. The abundance of manganese can lead to _______deficiency in plants.

11. Molybdenum is absorbed by plants in the form of _____________ ions.

12. Plants with zinc deficiency show reduced biosynthesis of _______________.

13. ___________ element helps in the electron transfer from H20 to PSII during photosynthesis.

14. The enzyme nitrogenase is involved in _________ Nitrogen

15. The best known nitrogen fixing bacterium is _________. Rhizobium

16. The conversion of ammonia to nitrate is called _____________. Nitrification

17. _____________ are the sites of nitrogen fixation in cyanobacteria. heterocysts

18. The best known nitrogen fixing symbiotic bacterium is ______________.

19. The nitrite reductase requires _________ and _________for its activity.