31.
Which two distinct microbial processes are responsible for the release of fixed nitrogen as dinitrogen gas $$\left( {{N_2}} \right)$$ to the atmosphere?
A
Anaerobic ammonium oxidation, and denitrification
B
Aerobic nitrate oxidation, and nitrite reduction
C
Decomposition of organic nitrogen, and conversion of dinitrogen to ammonium compounds
D
Enteric fermentation in cattle, and nitrogen fixation by Rhizobium in root nodules of legumes
Answer :
Anaerobic ammonium oxidation, and denitrification
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39.
Read the following four statements (A-D). (A) Both, photophosphorylation and oxidative phosphorylation involve uphill transport of protons across the membrane. (B) In dicot stems, a new cambium originates from cells of pericycle at the time of secondary growth. (C) Stamens in flowers of Gloriosa and Petunia are polyandrous. (D) Symbiotic nitrogen-fixers occur in free-living state also in soil. How many of the above statements are correct?
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40.
Farmers in a particular region were concerned that pre-mature yellowing of leaves of a pulse crop might cause decrease in the yield. Which treatment could be most beneficial to obtain maximum seed yield
A
Removal of all yellow leaves and spraying the remaining green leaves with 2,4,5- trichlorophenoxy acetic acid
B
Application of iron and magnesium to promote synthesis of chlorophyll
C
Frequent irrigation of the crop
D
Treatment of the plants with cytokinins alongwith a small dose of nitrogenous fertilizer
Answer :
Application of iron and magnesium to promote synthesis of chlorophyll