The process by which nitrogen gas is converted to ammonia by bacteria is called:
A. Ammonification
B. Denitrification
C. Nitrogen fixation
D. Nitrification
Answer: Option C
Solution (By JKExamLibrary)
Biological nitrogen fixation, carried out by symbiotic (Rhizobium) and free-living (Azotobacter) bacteria, reduces atmospheric N₂ to ammonia. Nitrification converts ammonia to nitrates, denitrification returns N₂ to air, ammonification releases ammonia from organic matter.
Explanation:
Mitochondria are double-membrane organelles with circular DNA (like prokaryotes) and 70S ribosomes, supporting the endosymbiotic origin. They are absent in prokaryotes. They are the site of aerobic respiration. The matrix contains enzymes for Krebs cycle. The inner membrane forms cristae, housing electron transport chain and ATP synthase.
Explanation:
Dengue is transmitted by Aedes aegypti, which also spreads chikungunya, Zika, and yellow fever. Anopheles transmits malaria, Culex filariasis, tsetse sleeping sickness.
Explanation:
Apical dominance is the phenomenon where the main central stem (apical bud) grows more strongly than the side stems (lateral buds). This is primarily controlled by auxin (specifically IAA), which is produced at the shoot apex and moves downwards, inhibiting the growth of lateral buds. Removal of the apical bud promotes lateral branching.
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