How are tectonic plates effecting the size of the Atlantic Ocean?

the shifting of the tectonic plates along the Mid-Atlantic Ridge are divergent (drifting apart). The Mid-Atlantic Ridge is a submerged mountain range that extends from Arctic Ocean to southern tip of Africa. Divergent boundaries occur along the spreading centers where the plates are moving apart, and a new crust is created by magma, pushing up from the mantle. The rate of spreading averages 2.5 centimeters per year. This seafloor spreading over the past 100-200 million years has caused the Atlantic Ocean to grow from a tiny inlet of water between Europe and Africa and Americas into vast ocean of today.As the spreading continues, the Atlantic will become larger.