First of all, there is a little room for doubt that heterogeneous classes provide a good environment for children of different learning capacities to learn from and help one another. For instance, someone who is good at academic subjects but weak in arts and music can learn to draw a picture or play a musical instruments from his peers. On the other hand, a student with musical aptitude may not be confident in his math ability and as such, he will need his classmates to explain a new science concept to him. In this sense, placing students of diverse interest and abilities in one class will enable them to collaborate with each other and develop into all-rounded people.
Despite the advantages of mixed-ability classes as illustrated above, I am convinced that streaming students bring more benefits to not only students but also teachers. While in a heterogeneous class, a teacher always need to develop two different lessons plan to cater to students of different capacities for learning, within a streamed class setting, the teacher is able to set a suitable pace for the class and maintain that pace. There is hardly any risk of leaving anyone behind. The entire class is challenged at a level gauged to be appropriate for the whole group. In this type of class setting students are able to motivate each other because they possess similar abilities. They can move ahead at the same pace because there are no major disparities in ability within the stream. Students are able to grow in confidence and self esteem