Concept: This question tests your knowledge of the functions controlled by different parts of the brain, specifically focusing on the vital roles of the medulla oblongata.

Why (D) is correct: The urge for drinking is primarily regulated by the hypothalamus, which contains osmoreceptors that detect changes in blood osmolarity and trigger thirst sensations. The medulla oblongata is not directly involved in this function.

Why other options are wrong:

• (A) Cardiovascular reflexes: The medulla oblongata contains the cardiovascular centre, which regulates heart rate, strength of heart contraction, and blood vessel diameter.
• (B) Respiration: The medulla oblongata houses the respiratory rhythmicity centre, controlling the basic rhythm of breathing.
• (C) Gastric secretions: The medulla oblongata plays a role in regulating gastric secretions through the vagus nerve (parasympathetic nervous system).

Common Mistake: Students often confuse the functions of the brainstem (medulla, pons, midbrain) with those of the diencephalon (hypothalamus, thalamus).

NEET Tip: Remember that the medulla oblongata is crucial for many involuntary, vital life functions, often summarized as 'reflex centres for survival'.

Correct Answer: (D)