At first scientists laughed at this idea and said it's impossible. Wegener didn't give up and had much evidence. Similar rocks, plants, and animals were on the coastlines of different continents and he found that this was because plate tectonics spread the continents. Many years later Harry Hess's ideas confirmed this theory.
Earth didn't always look like this. Alfred Wegener came up with a theory that hundreds of millions of years ago, all of the continents made up one super continent called Pangaea.
The collision of these plates can cause the formation of volcanoes, mountains, earthquakes, and trenches. The Mariana Trench is an example of this. You kind find this type of boundary in America on the Washington-Oregon coastline.
There are 3 types of plate boundaries. The first one is a convergent boundary which is when two plates slide toward each other causing the denser plate to subduct, or sink, under the other. There are 3 possibilities of this boundary based on the type of crust, oceanic or continental. The 3 types are oceanic-oceanic, oceanic-continental, or continental-continental convergent plate boundary.
This boundary can cause some hazards such as shallow earthquakes, some volcanic activity, submarine mountain ranges, ocean trenches or mid-ocean ridges, and sea-floor spreading. An example of this would be the Mid-Atlantic Ridge. This can be found in America between the North American plate and Eurasian plate.
The second type of plate boundary is a divergent boundary. This is when two plates move away from each other which leave a space in between. In this space molten rock rises from within earth and fills the space, forming new crust.