How does seafloor spreading provide further evidence of continental drift

Tectonic plates is caused by the immense heat of the earth's core that travel's through convection. 

A convergent boundary is a destructive plate boundary. It is a region where two or more tectonic plates move towards each other and collide. A good example of this is the San Andreas fault off the West Coast of America. When these plates collide, they can either cause an earthquake or a volcano to erupt. The intensity of the earthquake or volcano eruption depends on the speed at which the tectonic plates collide

An atom that has fewer electrons that protons is called a positive ion.