This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Physiology
Airway resistance 
Select and explain. 
A. Is increased if the lungs are removed and inflated with saline., B. Does not affect the work of breathing., C. Is increased in paraplegic patients., D. Is increased in asthma.
D: Is increased in asthma.
Answer: D: Is increased in asthma. 
Explanation: If the air flow becomes turbulent during rapid respiration, the energy required to move the air is greater than when the flow is laminar.