Fat students fall in more deep sleep than thin students. Putting it differently, it is difficult for the fat students to study well because they may have to fight with their tiredness than their study. Thus, it is obligatory for Korean students to take two physical classes like tennis, soccer, and so on per each year at their school.
I have asked you to post proofreading requests in the Editing and Writing Topics forum, with a better title than that.
I'm moving it now.