According to the theory of plate tectonics, which forces cause the movement of plates in the earth's crust? a. convection and the moon’s gravitational pull b. earthquakes and volcanic eruptions c. convection and gravity d. magnetism and energy from solar radiation

"Covection and gravity" are the forces among the choices given in the question that cause the movement of plates in the earth's crust, according to the theory of plate tectonics. The correct option among all the options that are given in the question is the third option or option "C". I hope the answer helped you.

Answer volcanic eruptionsseismic waves from earthquakes;

Why the planet stays in orbit is because of inertia (object stays in motion until a force changes it’s motion) also the atmosphere and gravity!