The alveoli are lined with water molecules, which are attracted to one another and tend to move closer together, making the alveoli collapse. Surfactant molecules get in between the water molecules, keeping them apart. What is the role of surfactant molecules in the alveoli?
1) Prevent the alveoli from collapsing
2) Attract water molecules to each other
3) Cause the alveoli to collapse
4) Move water molecules closer together