GEOLOGY

Detailed explanation-1: -Seafloor spreading creates new crust. Subduction destroys old crust. The two forces roughly balance each other, so the shape and diameter of the Earth remain constant.

Detailed explanation-2: -Seafloor spreading is caused by divergent plates, which are a specific type of tectonic activity that results in plates that move away from each other. Divergent plates that are located underwater at mid-ocean ridges and volcanic activity present at these locations result in newly formed seafloor.

Detailed explanation-3: -Lesson Summary. The theory of seafloor spreading explains that molten material moves in at the boundaries between tectonic plates pushing them apart as new oceanic crust is created. This process is called seafloor spreadingand it occurs at divergent boundaries.