They sit back there and they find out they don't do as well as students who sit up front. Those up front, according to one experiment, got better grades. They are also better students, while the ones in the back of the class are not so good. I think sitting in the middle is about best. In the answer, Student 2 loses sight of the original questions and begins to answer a different question, getting off track.
Students sitting in the back of a classroom find more distractions.
In back they are more likely to be with other students who are not good students, but who may be writing letters, daydreaming, or goofing off. Also, though students in the front may easily gain the instructor's attention and be able to communicate more easily with him or her, they may have difficulty responding to comments made by other class members, having to crane their neck or twist in their seat to reply. Student 3 gives a somewhat informal answer but covers the ground quite well and stays on track. I like reading this.