Question

Why is the subpolar low-pressure belt formed? 

Answer 1

1. Due to the earth's curvature, the area between two parallels gets reduced as we move towards the poles.
2. This results in less friction of the air with the earth's surface.
3. The air in this region is thrown out because of this reduced friction and also because of the earth's rotational motion. As its effect, the subpolar low-pressure belt formed.