Answer:
When a boy smells the aroma coming from the pot on the stove is actually detecting the chemicals coming from the air which comes from hot food that dissolves in the mucus present in the nasal cavity that carries tiny hairs made up of the nerve fibers that absorb these chemicals and excite or stimulate the olfactory receptors.
Various types of a distinct aroma or smell lead to a specific combination of the olfactory cells to make a specific smell. These combination patterns transported to the olfactory bulb along axons; a long extended neuron.
The sensory patterns or information encoding the smell of food present in the pot reaches the primary olfactory cortex in the brain, which is present on the anterior surface of the temporal lobe, and decodes accordingly.