The element required for chlorophyll formation in plants is

Step 1: Analyze the question We need the mineral element that plants require to form chlorophyll, the green pigment used in photosynthesis.

Step 2: Concept Chlorophyll's structure has a porphyrin ring with magnesium at the centre. Magnesium is the element that is part of the chlorophyll molecule itself. Iron is not part of the molecule, but it is essential for its synthesis, because it is needed for enzymes involved in making chlorophyll. Without iron, leaves develop chlorosis (yellowing), especially in young leaves.

Step 3: Check each option

• A. Iron: Required for chlorophyll formation (synthesis). Deficiency causes chlorosis. ✔
• B. Calcium: Builds cell walls (calcium pectate) and supports root growth. Not involved in chlorophyll.
• C. Phosphorus: Needed for ATP, DNA, and root development. Not involved in chlorophyll.
• D. Sulphur: Needed for amino acids like cysteine and methionine (proteins). Not involved in chlorophyll.

Magnesium, the element in the chlorophyll molecule, is not among the options. Of those given, iron is the one needed for chlorophyll formation, so the question is asking about iron.

Answer: A. Iron

Exam tip: Remember two key elements for chlorophyll:

• Magnesium is in the chlorophyll molecule (the "Mg in the middle").
• Iron is needed to make it (the "formation" wording in the question).

If you see "formation/synthesis" and magnesium isn't offered, choose iron. If the question says "constituent of chlorophyll" and magnesium is offered, choose magnesium.