The focal length of the natural eye lens is variable due to the action of the
A
Optical fluid
B
Ciliary muscle
C
Vitreous humor
D
retina nerves
Verified Correct Answer: B.
Step-by-Step Mathematical Solution
B. Ciliary muscle.
The ciliary muscles control the shape of the lens, allowing the eye to focus on objects at different distances by changing the focal length of the lens.
Source: WAEC / JAMB / NECO Classroom Archive (Record #74567)