Complex sentence: It allowed students with passing grades to participate in enrichment activities for 30 minutes during the day, while students with failing grades could work to improve their performance, which gave students with little time at home an opportunity to complete missing work.
Split into simpler sentences: It allowed students with passing grades to participate in enrichment activities for 30 minutes during the day, while students with failing grades could work to improve their performance. This gave students with little time at home an opportunity to complete missing work.