Why does srpeading of lava and ridge formation occur on the sea floor most commonly?

like.... why not on the ground? I don't get itWhy does srpeading of lava and ridge formation occur on the sea floor most commonly?
The mid-atlantic ridge is right on the line of two tectonic plates, this enables lava from the mantle to flow upwards. The convection of the mantle causes the two plates to spread even farther apart. Convection is the current of warm air rising, cooling down and then falling again. This cool air will then heat up in the depth of the mantle and start the process all over again.Why does srpeading of lava and ridge formation occur on the sea floor most commonly?
The sea floor is closer to the mantle than the surface.
Sea floor is land
probably because the crust at the sea floor is much thinner than on land, therefore the magma had less distance to travel.