Small hair-like structures called _______ are found in the upper part of the respiratory tract.
Show answer & explanation
Correct answer: B
Explanation
The correct answer is Option 2 i.e. Cilia.
Small hair-like structures called cilia are found in the upper part of the respiratory tract. These microscopic projections line the surfaces of the airways, including the nasal passages and the trachea. Functioning as a protective mechanism, cilia help to trap and remove debris, dust, and pathogens from the respiratory system. Through coordinated beating motions, cilia sweep mucus and trapped particles towards the throat, where they can be expelled through coughing or swallowing, thus helping to maintain respiratory health.