Which part of the body contains receptor cells involved in the olfactory system?

The part of the body that contains receptor cells involved in the olfactory system is the nasal passages. Within the nasal passages, specifically in a region called the olfactory epithelium, there are specialized olfactory receptor neurons. These neurons are responsible for detecting odor molecules in the air, which is essential for our sense of smell. When these receptors are activated by different odorants, they send signals to the brain that allow us to perceive and identify various smells.

The other options do not contain the specific receptor cells required for the olfactory process. The throat is primarily involved in swallowing and does not have olfactory receptors. The lungs are responsible for gas exchange and do not play a role in sensing smells. The mouth, while it does have taste receptors which contribute to flavor perception, is not part of the olfactory system where smell is encoded. Thus, the correct answer emphasizes the critical role of the nasal passages in olfaction.