according to the theory of plate tectonics, which forces cause the movement of plates in the earth's crust?

a.
earthquakes and volcanic eruptions

b.
magnetism and energy from solar radiation

c.
convection and gravity

d.
convection and the moon’s gravitational pull

C.  convection and gravity  

Explanation:

The theory of plate tectonic suggest that the Earth's layer is divided into seven major plates which glide over each other. Convection force and gravity is responsible for the movement of these plates.

The molten rock in the mantle rise up due to intense heat produced by Earth's core. As they rise, they eventually cool down and sink again. This convection process continues and leads to movement of plates. The force that causes this motion is the gravity. When one plate rubs with the other plate, earthquake occurs.

it provides an alternative energy pathway for the reaction to proceed.

a catalyst is a substance that speeds up the rate of a chemical reaction but is not consumed during the course of the reaction.

catalysts increase the rate of reaction without being used up. they do this by lowering the activation energy needed. with a catalyst, more collisions result in a reaction, so the rate of reaction increases. different reactions need different catalysts.

a catalyst works by providing an alternative reaction pathway to the reaction product. the rate of the reaction is increased as this alternative route has a lower activation energy than the reaction route not mediated by the catalyst.