How does the magnetosphere support life on earth?

a.
it circulates heat between the poles of the planet.
b.
it shields the planet from harmful particles emitted by the sun.
c.
it provides an innate navigational system to life forms.
d.
it creates ocean and air currents that dissipate heat.

A55-kg pilot flies a jet trainer in a half vertical loop of 1200-m radius so that the speed of the trainer decreases at a constant rate. knowing that the plane has a speed of 550 km/h at point a, and the pilot experiences weightlessness at point c (i.e., the normal force from the seat bottom is zero), determine (a) the deceleration of the plane, (b) the force exerted on her by the seat of the trainer when the trainer is at point b.