Question

Identify the correct statement.

(a) In amniotes last nerve is spinal accessory.

(b) In non-amniotes last nerve is vagus.

(c) Optic is shortest nerve.

(d) Olfactory nerves has mixed fibres.

Answer 1

The correct option is: (b) In non-amniotes last nerve is vagus.

Explanation:

10 pairs of cranial nerves are present in anamniotes (fishes and amphibians) and 12 pairs occur in amniotes (reptiles, birds and mammals). In anamniote the cranial nerves are Olfactory, Optic, Occulomotor, Trochlear, Trigeminal, Abducens, Facial. Auditory, Glossopharyngeal and Vagus. ln amniotes two more cranial nerves, spinal accessory and hypoglossal nerves are present in addition to the above ten pairs of cranial nerves.