Complex sentence: After basketball became established in American colleges, the professional game followed; the American National Basketball Association (NBA), established in 1949, grew to a multibillion-dollar enterprise by the end of the century, and basketball became an integral part of American culture.
Split into simpler sentences: After basketball became established in American colleges, the professional game followed. The American National Basketball Association (NBA), established in 1949, grew to a multibillion-dollar enterprise by the end of the century, and basketball became an integral part of American culture.