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O-LevelBiologyCoordination & Response5090/12 · May/June 2014 · Q221 Mark

Opticians sometimes place drops of a chemical in a patient's eye to keep the pupil wide open. Which muscles contract when this chemical is used?

Aciliary muscles
Bcircular iris muscles
Cmuscles that move the eyeball
Dradial iris muscles

✓ Correct answer

D: radial iris muscles

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About this question

Topic
Coordination & Response, O-Level Biology (syllabus 5090). Multiple choice, 1 mark.
Source
O-Level Biology, May/June 2014 Paper 1 Variant 2, question 22.

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