Final answer:
True, the ciliated cells of the nasal mucosa do move contaminated mucus towards the pharynx as part of the mucociliary escalator, which helps to clear the airways of trapped particles and pathogens.
Step-by-step explanation:
The statement that the ciliated cells of the nasal mucosa propel contaminated mucus posteriorly toward the pharynx is True. Cilia are microscopic, hair-like structures that are capable of beating in unison to move mucus, which traps particles and pathogens, towards the throat where it can be expelled from the body or swallowed into the acidic environment of the stomach. This mechanism is often referred to as the mucociliary escalator, which is crucial in protecting the respiratory system from infection and debris. When we cough and expel phlegm, we are actively participating in this process of clearing contaminants from our airways.