O-LevelBiologyGenetics & Variation5090/11 · Oct/Nov 2017 · Q391 Mark

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

This question uses a diagram from the original paper, which isn't shown here. Open the full paper from the past papers archive to see it.

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, Oct/Nov 2017 Paper 1 Variant 1, question 39.

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