Explain the difference between constructive and destructive plate boundaries?

Overall, there are 4 types of plate boundaries, with constructive and destructive being opposites. A constructive plate boundary is where two plates are slowly moving away from each other, allowing for magma to come up from the mantle and create new crust (see diagram). An example of this is the mid Atlantic ridge which runs down the centre of the Atlantic Ocean where the Eurasian plate and North American plate are moving in opposite directions. On the other hand, destructive plate boundaries occur where two plates meet as they are moving into the same space, and one plate is forced under the other (see diagram). This often occurs where an oceanic plate and continental plate meet, with the oceanic plate being forced under the continental plate due to tectonic plate density differences. The oceanic plate is melted in the mantle, creating more magma, and often allowing for mountain chains and volcanoes to be created on the continent.