according to the theory plate tectonics, the earth's crust is broken into about 12 plates that  float  on hotter, softer rocks in the underlying mantle. these plates move about the earth, just inches each year. these slight movements are responsible, in great part, for the earthquakes and volcanoes that happen on earth. what is the source of energy that drives this plate movement?

I think that the source that drives this plate movement is the magnetisim from the 2 poles.I just think this because magnetisim can produce a large amount of heat.

where sediments deposit and form new layers

no

explanation:

since the earth is flattened at the poles and bulges at the equator, geodesy represents the figure of the earth as an oblate spheroid. the oblate spheroid, or oblate ellipsoid, is an ellipsoid of revolution obtained by rotating an ellipse about its shorter axis.