The teacher has a great role in setting up the class. Whom do you call out the most? The learned or the learning fellows. Who are you there for? Do you want to focus on quick learners or slow learners? The atmosphere we set on this basis is very important as we give the vibe that, the education is striving for the perfection the grade demands, and less is emphasized on who is falling behind.
If only teachers are there to teach? Whom we should concentrate more to make it all-learning for everyone rather than for the people who are in the grade level.