The correct answer will be option-It traps particles such as dust and pollen.
Explanation:
The mucus produced in the lungs is also known as the airway surface liquid or ASL and the mucus formed inside the lungs is known as phlegm. The mucus is composed of the water, ions and the macro-molecules which can trap and has anti-protease and anti-microbial activity.
This mucus forms a thin layer of the fluid in the luminal surface of the airway to which protects the lungs from the foreign particles and chemicals which can enter.
Thus, option-It traps particles such as dust and pollen is the correct answer.
I think its C. hormones act on muscles and glands only. Because hormones act on cells, tissues, organs etc. So this is incorrect and the rest of them are correct.
