Why do earthquakes and volcanoes occur at plate boundaries?

Earthquakes are caused by transform plates, which are two plates sliding past each other.

Volcanoes are caused by convergent plates, which is when crust is consumed.

Mountains are caused by collisional plates, which is when two land masses collide.

the tectonic plates collide and the ground (earth) pushes upwards and the molten rock pushes up too and causes a volcano to form