Biology 5090 · O Level · Inheritance

Inheritance — practice question

Earlobes may be joined to the cheek or ‘free’ (unattached). A single gene determines this feature. The allele for attached earlobes is recessive. The diagram illustrates how earlobe attachment is inherited in one family. Which two individuals have to be heterozygous for earlobe attachment?

  • A1 and 7
  • B3 and 4
  • C5 and 8
  • D6 and 9

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