Which best states the theory of plate tectonics?

a. earth's layers consist of the crust, the mantle, the outer core, and the inner core.

b. earth's surface is made of different sections of rock that move apart and collide.

c. earth's most active volcanoes and earthquakes occur in the ring of fire.

d. earth's continents were once joined together as one landmass.

The theory of plate tectonics states that the Earth's surface, the upper mantle and crust, was once made up of enormous rock plates that broke into smaller pieces approximately 300 million years ago. These smaller, broken plates form a more fluid rock surface in the mantle. Over time, the plates move and morph into natural land boundaries. This explains natural land phenomena, such as earthquakes and tsunamis. So A