Single Answer MCQ
Q-00001700
How does the eye lens change its thickness to adjust its focal length?
1
By changing the size of the cornea
2
By changing the shape of the iris
3
By contracting and relaxing the ciliary muscles
4
By adjusting the size of the pupil
Answer and Solution
Answer
C. By contracting and relaxing the ciliary muscles
Solution:
The eye lens changes its thickness to adjust its focal length by the contraction and relaxation of the ciliary muscles. These muscles alter the shape of the lens, making it thicker or thinner as needed to focus on objects at different distances. Therefore, the correct answer is 'By contracting and relaxing the ciliary muscles'.
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