Which statement is NOT true of both meiosis and mitosis?

Analyze the question: We need the statement that is NOT true of both processes, meaning something that happens in one but not the other.

Concept: Mitosis and meiosis share many features of nuclear division. Both involve:

• Chromosomes condensing (thickening and shortening) in prophase
• Breakdown of the nuclear envelope
• Spindle formation
• Chromosomes lining up at the equator (metaphase plate)

The key difference is in the chromosome number of the daughter cells:

• Mitosis: one division gives 2 daughter cells with the same chromosome number as the parent (diploid → diploid).
• Meiosis: two divisions give 4 daughter cells with half the chromosome number (diploid → haploid).

Checking each option:

• A. Aligning of chromosomes at equator: happens in metaphase of mitosis, and in metaphase I and II of meiosis. True of both.
• B. Disintegration of nuclear material: the nuclear membrane and nucleolus break down in prophase of both. True of both.
• C. Formation of spindle apparatus: both use spindle fibres to move chromosomes. True of both.
• D. Halving the number of chromosomes: only meiosis does this. Mitosis keeps the chromosome number constant. Not true of both.
• E. Thickening and shortening of chromosomes: chromosomes condense in prophase of both. True of both.

Answer: D. Halving of the chromosome number is the special feature of meiosis only.

Exam tip: Whenever you see "halving", "reduction division", "haploid" or "gametes", think meiosis only. "Identical daughter cells" and "growth/repair" point to mitosis only.