Answer: Wilting and dark green leaves; young leaves may show chlorosis; lignification reduced.
- A Uniform yellowing spreading evenly across leaves of nearly every age on the plant
- B Wilting and dark green leaves; young leaves may show chlorosis; lignification reduced
- C Progressive decay and blackening spreading gradually throughout the entire root system
- D Purple discoloration spreading visibly along the full length of the main stem
Correct answer: B. Wilting and dark green leaves; young leaves may show chlorosis; lignification reduced
Explanation: Copper is a component of plastocyanin (photosynthesis electron transport), cytochrome c oxidase, and lignin synthesis. Deficiency causes dark green, wilted young leaves, die-back of shoot tips, and reduced pollen viability.
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.