Which of the following is correct about nitrous oxide?

Correct Answer: C

Rationale: Nitrous oxide (N2O) is an inhalation anesthetic with distinct properties. 'It is the only true gas,' is correct because it's stored as a gas at room temperature, unlike volatile liquids (e.g., sevoflurane), per anesthesiology texts (e.g., Barash). 'It cannot be used for rapid induction,' is false; it's quick-acting, though weak alone. 'It has an unpleasant odour,' is incorrect; it's odorless or slightly sweet. 'It is generally used as a volatile adjunct,' is true but less defining than its gaseous state. N2O's unique physical property as a true gas distinguishes C as the accurate answer.

Correct Answer: B

Rationale: The greater omentum, a peritoneal fold, lies anterior to the small intestine, draping over it. 'Anterior,' is correct, per anatomical positioning (e.g., Netter's Atlas). 'Posterior,' is incorrect; it's behind the stomach, not intestine. 'Superficial,' is vague but implies skin-level. 'Deep,' suggests below, not above. Anterior's directional accuracy makes B the precise answer.

Correct Answer: D

Rationale: Arteries withstand pulse pressure via elasticity. 'An elastic tunica media,' is correct, allowing stretch and recoil (e.g., aorta), per anatomy (e.g., Ross). 'A thick tunica interna,' is less relevant. 'A rigid tunica media,' resists stretch. 'A flexible endothelium,' is minor. Elasticity in the media makes D the accurate answer.

Correct Answer: A

Rationale: The thyroid gland's functional unit is the follicle, where thyroid hormones are synthesized and stored. 'Follicle,' is correct, per histology texts like Ross and Pawlina, consisting of follicular cells around colloid. 'Acini,' are exocrine gland units (e.g., pancreas). 'Islets of Langerhans,' are pancreatic endocrine units. 'Alveoli,' are lung units. Follicles' role in T3/T4 production distinguishes A as the accurate answer, specific to thyroid anatomy.

Correct Answer: C

Rationale: Monosaccharides are simple sugars, single units not hydrolyzed further. 'Maltose,' is correct as the exception, a disaccharide of two glucose units, per biochemistry texts like Lehninger. 'Glucose,' 'Fructose,' and 'Galactose,' are monosaccharides, basic sugar building blocks. Maltose's dimeric structure, requiring hydrolysis, distinguishes C as the accurate answer, unlike the single-unit sugars.