Final answer:
The nasal cavity is divided into left and right portions by the nasal septum, formed by the perpendicular plate of the ethmoid bone, vomer bone, and septal cartilage. The conchae in the lateral walls enhance the functions of the nasal cavity.
Step-by-step explanation:
The nasal cavity is divided into left and right portions by the nasal septum. The nasal septum is formed by the perpendicular plate of the ethmoid bone, vomer bone, and septal cartilage. Each lateral wall of the nasal cavity contains bony projections called the superior, middle, and inferior nasal conchae. These structures increase the surface area of the nasal cavity and disrupt the flow of air, allowing for its cleaning and warming.