Biology 5090 · O Level · Inheritance

Inheritance — practice question

Earlobes may be either attached to the cheek or ‘free’ (unattached). One gene controls this feature. The allele that causes attached earlobes is recessive. The diagram illustrates how attached earlobes are 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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