Magnesium's Role in Chlorophyll Synthesis

Steps:

• Identify magnesium's primary function in plants: central atom in chlorophyll molecule.
• Link deficiency to impact: without Mg, chlorophyll cannot form, impairing photosynthesis.
• Connect to growth: reduced photosynthesis limits energy production, causing poor growth.
• Evaluate options: match symptoms to mineral roles, eliminating unrelated deficiencies.

Why C is correct:

• Chlorophyll's structure requires Mg²⁺ ion at its core (porphyrin ring), enabling light absorption for photosynthesis.

Why the others are wrong:

• A: Cellulose synthesis depends on glucose from photosynthesis and carbon, not Mg.
• B: Amino acid production requires nitrogen (e.g., nitrates), not magnesium.
• D: Mg deficiency affects specific uptake but doesn't broadly block all mineral ion absorption.

Final answer: C