In the human eye, the 'macula lutea' and its central depression, the 'fovea centralis', are significant because the fovea contains: MCQ with Answer and Explanation

In the human eye, the 'macula lutea' and its central depression, the 'fovea centralis', are significant because the fovea contains:
A. An equal number of rods and cones
B. Only rods, providing high sensitivity to dim light
C. Only cones, providing the sharpest central vision and color discrimination
D. The blind spot where the optic nerve exits
Answer: Option C
Solution (By JKSSB Mock Tests)
The macula lutea is a yellowish spot near the center of the retina. Its central depression, the fovea centralis, is the point of sharpest vision. The fovea is packed exclusively with cone cells and lacks blood vessels and rods. This high density of cones, combined with the displacement of overlying retinal layers, allows for maximum visual acuity and color discrimination in bright light. The blind spot is the optic disc.

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In an ecological food chain, the 10% law of energy transfer implies that if producers fix 10,000 kcal of energy, the energy available to the tertiary consumers will be:
A. 100 kcal
B. 10 kcal
C. 1,000 kcal
D. 1 kcal

Correct Answer: Option B


Explanation:
According to Lindeman's 10% law, only about 10% of the energy from one trophic level is transferred to the next; the rest is lost as heat through respiration. Producers (Trophic Level 1) have 10,000 kcal. Primary consumers (Level 2) get 10% of 10,000 = 1,000 kcal. Secondary consumers (Level 3) get 10% of 1,000 = 100 kcal. Tertiary consumers (Level 4) get 10% of 100 = 10 kcal.

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The organ that is responsible for the detoxification of ammonia to urea in humans is the:
A. Liver
B. Pancreas
C. Spleen
D. Kidney

Correct Answer: Option A


Explanation:
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Typhoid fever is caused by which bacterium?
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Correct Answer: Option A


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