Research shows that teenagers require at least 8 to 9 hours of sleep each night. Should this word be additionally, therefore because or sense and then it says school should consider implementing later start time, so teens can get the sleep they need.
The word that best fits in this context is "therefore."
Research shows that teenagers require at least 8 to 9 hours of sleep each night. Therefore, schools should consider implementing later start times, so teens can get the sleep they need.