Questions: Most inspired particles such as dust fail to reach the lungs because of the ciliated mucous lining in the nose abundant blood supply to nasal mucosa porous structure of turbinate bones action of the epiglottis

The answer is the first one: the ciliated mucous lining in the nose.

Explanation for each option:

1. Ciliated mucous lining in the nose: This is correct. The ciliated mucous lining in the nose traps dust and other particles. The cilia (tiny hair-like structures) move the mucus, along with the trapped particles, towards the throat where it can be swallowed or expelled. This mechanism prevents most particles from reaching the lungs.

2. Abundant blood supply to nasal mucosa: This is incorrect. While the nasal mucosa does have an abundant blood supply, which helps warm and humidify the air, it does not play a direct role in trapping particles.

3. Porous structure of turbinate bones: This is incorrect. The turbinate bones (or nasal conchae) help to increase the surface area of the nasal passages and aid in warming and humidifying the air, but their porous structure does not directly trap particles.

4. Action of the epiglottis: This is incorrect. The epiglottis is a flap of tissue that covers the trachea during swallowing to prevent food and liquid from entering the lungs. It does not play a role in trapping inhaled particles.

Summary: Most inspired particles such as dust fail to reach the lungs because of the ciliated mucous lining in the nose, which traps and moves particles away from the respiratory tract.