Final answer:
The cilia within the respiratory system are responsible for removing foreign matter from the lungs, sweeping trapped particles and mucus out of the airways for expulsion.
Step-by-step explanation:
The structure within the respiratory system that is responsible for removing foreign matter from the lungs is B. Cilia. These hair-like structures line the bronchi and bronchioles, and their main function is to sweep mucus, which traps pathogens and debris, superiorly towards the throat where it can be swallowed and expelled.
The cilia are part of the lining of the conducting zone, which is mostly composed of pseudostratified ciliated columnar epithelium with goblet cells. This mucus-cilia system is an essential defense mechanism that helps keep the airways and lungs clear of inhaled particles, allowing efficient gas exchange to occur in the alveoli, where the respiratory membrane is located.