You did not discuss the situation of disruptive students in class. You changed the prompt discussion totally. You only discussed students who have a different character from others. Which, as can be seen in your discussion, does not relate to disruptiveness in class. You have to remember that disruptive student can prevent his classmates from learning either in a group or classroom setting because he does not allow the lesson to be taught properly. As such, he prevents the other students from learning. Which is why the teachers would like to separate them from the rest of the class.  
  
You probably know the disruptive student as the class clown. The one who always makes the class laugh or is always scolded by the teacher for not paying attention, or he is doing something opposite to what the rest of the class is doing. These are the disruptive actions that prove to be a negative influence on the others. He is a negative influence because he breaks the concentration and focus from the class lesson onto his antics instead. The class ends with the teacher just scolding the disruptive student, and the rest of the class was not taught the lesson for the day.  
  
So your overall discussion is incorrect. It is not related to the given discussion topic. You have to learn to analyze the question before you start writing. When you make a mistake in understanding the keyword, in this case "disruptive", you will not be able to discuss the essay based on the expected information or standards. The point of the essay, is that the disruptive students do not learn in the manner that the rest of the class does, so they should be taught in a separate method or class.  
  
It is true, school is a form of social environment. However, it is a learning social environment. Students do not go to school to be entertained, they go to school to learn, develop their skills, and nurture their natural abilities. A disruptive student prevents that learning environment from succeeding because he is there not to learn, but just to have fun. Your overall defense is improper. While there are no right or wrong answers, your response should at least show that you understand the main point of the discussion. In this case, you failed to understand what the discussion is all about. The only time a disruptive student would be welcome in the learning community would be during recess, lunch break, and after school during extra curricular activities. That is the only time when the learning method is informal and would allow him to be as disruptive as he wishes to be. That is the only social learning time the students have outside of formal class hours.  
  
As of now, your essay is not worth scoring yet. All I can do with your first essay is assess your English comprehension and writing skills. Unfortunately, your comprehension skills are not strong enough and your writing skills need to be further honed. You do not know how to find the keywords and analyze the topic for a proper discussion yet. You have to outline the discussion to find the keywords:  
  
Topic: Disruptive school students have a negative influence on others.  
Discussion Reason: Students who are Disruptive school students should be grouped together and taught separately.  
Discussion Question: Do you agree or disagree?  
  
You failed to understand the discussion reason. The keywords and phrases being: Disruptive school students, a negative influence on others. Students who are noisy and disobedient, grouped together and taught separately.  
  
Your discussion paragraphs should have focused on a defense or agreement based on the 3 keywords. One paragraph for each keyword topic. The discussion paragraphs would have been:  
  
Reasoning 1: When a student tends to distract (synonym for disruptive) the class , his classmates cannot learn well.  
Reasoning 2: His being troublesome (another synonym) makes him an unfavorable influence on his peers because...  
Reasoning 3: Based on these considerations, it appears that segregating (synonym for separately) the disorderly student might have...  
  
The above discussion outline is what I would have used. You may have used a different outline because you disagreed with the statement, but you still need to use the synonyms for the keywords in your presentation as I did above.