Ms. long is a first grade teacher and uses cooperative learning in her classroom. in creating groups of students she will equally distribute high achieving, moderate achieving, and low achieving students so there is one student of each category in every group. based upon the skills of each student, ms. long knows that the high achieving students can the modern achieving students, and in turn, the moderate achieving students can the low achieving students. it is clear that ms. long is using the principle of in her classroom.