▶️ Answer/Explanation
To focus on a nearby object (the fly), the eye undergoes accommodation. The ciliary muscles (Q) must contract, which reduces the diameter of the ring they form. This contraction causes the suspensory ligaments (S) to lose their tension and become slacker. With the outward pull removed, the elastic lens (R) naturally springs into a more convex or “fatter” shape. This increased curvature increases the refractive power of the lens, allowing the light rays to be focused correctly on the retina.
✅ Answer: (C)
✅ Answer: (C)
▶️ Answer/Explanation
The endocrine glands shown sitting atop the kidneys are the adrenal glands. These glands release the hormone adrenaline (epinephrine) during “fight or flight” situations. Adrenaline prepares the body for immediate action by triggering several physiological changes. One of these primary responses is the dilation of the pupils (an increase in pupil diameter) to allow more light into the eyes, improving visual awareness. Other effects include an increase in heart rate and blood glucose levels, making options (A) and (B) incorrect. Secondary sexual characteristics are controlled by sex hormones from the gonads, not adrenaline.
✅ Answer: (C)
✅ Answer: (C)
▶️ Answer/Explanation
When the ciliary muscles contract, the ring of muscle becomes smaller in diameter. This reduces the tension on the suspensory ligaments, making them slack. As a result, the elastic lens is no longer pulled thin and becomes more convex (rounder). A rounder lens has a higher refractive power, meaning there is more refraction of light rays as they pass through the lens to focus on the retina. This state is normally used for viewing near objects.
✅ Answer: (B)
✅ Answer: (B)