O-LevelBiologyGenetics & Variation5090/12 · May/June 2021 · Q381 Mark

Earlobes can either be attached to the cheek or be 'free' (unattached). This characteristic is controlled by a single gene. The allele for attached earlobes is recessive. The diagram shows the inheritance of attached earlobes in one family. [Figure 38.1] Which two individuals must be heterozygous for earlobe attachment?

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A1 and 7

B3 and 4

C5 and 8

D6 and 9

✓ Correct answer

A: 1 and 7

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Topic: Genetics & Variation, O-Level Biology (syllabus 5090). Multiple choice, 1 mark.
Source: O-Level Biology, May/June 2021 Paper 1 Variant 2, question 38.

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