The idea that magma rises up at rift valleys and crust is being destroyed at trenches describes the theory of

The idea that magma rises up at rift valleys and crust is being destroyed at trenches describes the theory of plate tectonics. It is a theory where the lithosphere is being divided into plates. These plates are a result of the continuous rising of magma causing the crust and rift valleys to be destroyed. These plates continuously moves and the movement is a result of the convection process in the mantle. Hot substances near the core would rise up while the colder part would sink. The convection would push and spread apart ocean ridges. Also, it pulls and sinks subduction zones.

It's true it didin't work becouse britain continued trading with it's colonies and the system hurt economies of the countries that used it