<prompt> The roof of the olfactory region is formed by ?Nasal boneCribriform plate of ethmoidSphenoidTemporal bone  <response>: Ans. is b i.e., Cribriform plate of ethmoid The olfactory mucosa lines the upper one-third of nasal cavity including the roof formed by cribriform plate and the medial and lateral walls up to the level of superior concha turbinate. 