This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory System, Subject name: Physiology
Identity '1' in the illustration depicting compliance of lungs: 
Select and explain. 
A. Inspiration, B. Expiration, C. Inspiration Air filled, D. Expiration air filled
A: Inspiration
Answer: A: Inspiration 
Explanation: Ans. A. InspirationThe illustration shows a Pressure-volume curve of the lung during inspiration and expiration.