Eye Structures for Accommodation

Steps:

• Recall that focusing near objects requires ciliary muscles to contract, relaxing suspensory ligaments to thicken the lens.
• In standard eye diagrams, structure 1 is typically the ciliary muscles, which control lens shape.
• Structure 2 is the suspensory ligaments, which attach the lens and adjust tension based on muscle action.
• Match to choices: A correctly orders ciliary muscles first, then suspensory ligaments, aligning with diagram flow.

Why A is correct:

• Ciliary muscles contract to slacken suspensory ligaments, enabling lens bulging for near focus per accommodation mechanism.

Why the others are wrong:

• B: Iris and pupil control light entry, not lens focusing.
• C: Reverses order; suspensory ligaments do not precede ciliary muscles in standard labeling.
• D: Identical to C, incorrect order for diagram.

Final answer: A