The given type of cells are found in all of the following parts of the respiratory tract EXCEPTA. trachea.B. alveolus.C. bronchus.D. nasal cavity.CiliaMucus

The question is asking which part of the respiratory tract does not contain the given type of cells, which are cilia and mucus.

Here's a brief explanation of each option:

A. Trachea: The trachea, or windpipe, is lined with ciliated cells that produce mucus. This mucus traps small particles, like dust and germs, that may enter the trachea. The cilia then move the mucus upward and out of the respiratory system, helping to keep the lungs clean.

B. Bronchus: The bronchi, like the trachea, are also lined with ciliated cells that produce mucus for the same purpose.

C. Alveolus: The alveoli are tiny air sacs in the lungs where the exchange of oxygen and carbon dioxide takes place. They do not produce mucus or have cilia. Their walls are extremely thin to allow for the exchange of gases.

D. Nasal cavity: The nasal cavity is the first part of the respiratory tract where air enters the body. It is lined with ciliated cells that produce mucus to trap particles and moisten the air.

So, the answer is B. Alveolus. The alveoli do not contain cilia or mucus cells.