What statement is not true of Cillia in the respiratory tract?

Cilia in the respiratory tract do not actively propel mucus and trapped particles toward the lungs; rather, they sweep mucus and debris upward toward the throat for expulsion. Additionally, cilia are not involved in gas exchange; their primary function is to keep the airways clear of pathogens and contaminants. Therefore, any assertion suggesting that cilia facilitate direct respiration or gas exchange would be false.