Biology 5090 · O Level · Nuclear division

Nuclear division — practice question

A person with Down’s syndrome is born with 47 chromosomes in each cell, rather than 46. What might have caused this?

  • AA mutation happened during the production of the egg cell.
  • BMore than one sperm fused with the egg at fertilisation.
  • CRadiation caused a change in structure of a gene in the father’s sperm.
  • DThe mother was exposed to harmful chemicals while she was pregnant.

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