Surfactant prevents this collapse by reducing the surface tension of the fluids that line the lungs and helping to equalize the pressures between large and small air spaces. Surface tension is a measure of the attraction molecules of a fluid have for each other.
Buffalo Bill Cody, who later became famous for his Wild West Show, was a rider for the Pony Express and wrote of his experiences. We join Bill's story as he is hired - at the age of 15 - to ride a section of the trail that lies in modern-day Wyoming:
Ponyboy Curtis - The novel's fourteen-year-old narrator and protagonist, and the youngest of the greasers. Ponyboy's literary interests and academic accomplishments set him apart from the rest of his gang. Because his parents have died in a car accident, Ponyboy lives with his brothers Darry and Sodapop.