Which cranial nerve is responsible for the sense of smell?

The olfactory nerve is responsible for the sense of smell. It is the first cranial nerve and is specifically designed to carry sensory information related to odors from the nasal cavity directly to the brain. This nerve consists of small fibers that pass through the cribriform plate of the ethmoid bone and connect to the olfactory bulb, which processes the signals before transmitting them to various areas of the brain responsible for interpreting smell.

The optic nerve is primarily involved in vision and carries visual information from the retina to the brain. The trigeminal nerve is responsible for sensation in the face and motor functions like biting and chewing, but it does not play a direct role in olfactory processes. The facial nerve is primarily known for controlling the muscles of facial expression and also carries taste sensations from the anterior two-thirds of the tongue, but it does not have a function related to the sense of smell. This specialization of the olfactory nerve is what makes it the correct answer for the sense of smell.