The diameter of a motor nerve fibre is

Correct Answer: D

Rationale: Motor nerve fibers (alpha motor neurons) are large, myelinated, and typically 12-20 micrometers in diameter to ensure fast conduction to muscles. Smaller diameters are for sensory or unmyelinated fibers.

Correct Answer: B

Rationale: The sensory root of CN VII is the nervus intermedius, carrying taste and parasympathetic fibers, exiting via the internal acoustic meatus, not foramen ovale.

Correct Answer: D

Rationale: The midbrain contains oculomotor (CN III) nuclei, lying between the pons and diencephalon in the posterior cranial fossa.

Correct Answer: B

Rationale: The anterior cerebral artery supplies the medial cortex (contralateral leg, micturition/defecation areas). Middle cerebral supplies lateral cortex (arm, face, speech).

Correct Answer: B

Rationale: Anterior roots contain efferent motor fibers and some sympathetic fibers (T1-L2), joining posterior roots at the spinal nerve.