Why does homework exist if it causes so much long and short term stress, lack of sleep, and even depression in some cases? all of these things are extremely bad especially during the developmental periods that youths are going through. the list goes on along with the homework.

A long time ago when schools were first created, they didn't have sports teams or after school clubs. It was morning to afternoon and that was it.
Since most students were fascinated by the things the teacher taught them, they wanted to bring it home and show their family what they were learning in school. So then, homework was created and hasn't stopped since. A good way to deal with homework is to reward yourself for each thing you get done or take breaks every 1/2 hour in order to keep up the good work! Also, you should do your homework as soon as possible to keep everything you learned fresh in your mind, you're more likely to get better accuracy on the assignment. Even though children are developing, schoolwork should be put above going to the mall, sports practice, etc...