Complex sentence: Fells attended Fullerton Union High School in Fullerton, California where he was selected to the All-CIF Southern Section II-A second team as a junior while averaging 17 points and 10 rebounds as the team's center.
Split into simpler sentences: Fells attended Fullerton Union High School in Fullerton, California, where he played basketball. He was selected to the All-CIF Southern Section II-A second team as a junior while averaging 17 points and 10 rebounds as the team's center.