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
A line of reasoning that presents the opposite side of the author's argument is called (I believe) a counterargument. It states exactly the different thing from what you have first stated.
