Concept: This question tests your understanding of the key differences between the sympathetic and parasympathetic divisions of the autonomic nervous system (ANS), focusing on their physiological effects and neurotransmitters.

Why (D) is correct: The statement says the sympathetic system constricts the pupil and the parasympathetic system dilates it. This is incorrect. The sympathetic nervous system is responsible for the 'fight or flight' response, which includes pupil dilation (mydriasis) to allow more light in for better vision. Conversely, the parasympathetic nervous system is responsible for 'rest and digest' functions, which include pupil constriction (miosis).

Why other options are wrong:

• (A) The sympathetic system increases heart rate and the parasympathetic system decreases it. This is correct.
• (B) The sympathetic system inhibits salivation and the parasympathetic system stimulates it. This is correct.
• (C) The sympathetic system inhibits peristalsis and the parasympathetic system stimulates it. This is correct.

Common Mistake: Students often confuse the specific effects of sympathetic and parasympathetic stimulation on various organs, especially the pupil and heart rate.

NEET Tip / Mnemonic: Remember 'Sympathetic = Stress/Speed up' (except digestion) and 'Parasympathetic = Peace/Pause'. For pupils, think 'fight or flight' needs more light, so pupils dilate (sympathetic).

Correct Answer: (D)