Here's why:
* Divergent boundaries are where tectonic plates move apart from each other.
* This movement allows magma from the Earth's mantle to rise to the surface, creating new oceanic crust.
* As this new crust forms, it pushes older crust further away, resulting in the spreading of the seafloor.
This process is known as seafloor spreading and is a key part of the theory of plate tectonics. It's responsible for the formation of mid-ocean ridges, which are underwater mountain ranges where the spreading occurs.
