Complex sentence: Karli, 17, and Tanya, 16, had no choice but to take on the boys when their school, Chartiers-Houston High School, didn't sport a girls tennis team due to lack of interest.
Split into simpler sentences: Karli, 17, and Tanya, 16, were students of Chartiers-Houston High School. They became involved in male tennis when the school failed to provide a girls tennis team due to lack of interest.