Final answer:
Surfactant is a complex mixture of phospholipids and lipoproteins that is produced by type II alveolar cells in the lungs to reduce surface tension in the alveoli.
Step-by-step explanation:
Surfactant is a complex mixture of phospholipids and lipoproteins that is produced by type II alveolar cells in the lungs. It works to reduce the surface tension between the alveoli tissue and the air within the alveoli.