Answer: chlorosis.
- A chlorosis
- B necrosis
- C etiolation
- D abscission
Correct answer: A. chlorosis
Explanation: Chlorosis is the loss of green colour due to reduced chlorophyll formation.
Atmospheric N₂ is fixed into ammonia by nitrogen-fixing bacteria (protected from oxygen by leghaemoglobin in root nodules), converted to nitrate via nitrification for plant uptake, and eventually returned to the atmosphere as N₂ via denitrification, completing the cycle.
Concept context
Essential mineral elements, their roles and deficiency symptoms. Nitrogen fixation and soil nutrition.