Lung cells secrete this substance which prevent alevoli from collapsing in between breaths?

The correct answer is Surfactant.

Explanation

- The inner surface of the alveoli is lined by type II pneumocytes that secrete surfactant.

- Surfactant is a complex mixture of lipids and proteins that reduces surface tension at the air-liquid interface in the alveoli.

- This prevents the alveoli from collapsing between breaths.