Here's why:
* Divergent boundaries are where tectonic plates move apart.
* This separation allows magma from the Earth's mantle to rise up and cool, forming new crust.
* This process is called seafloor spreading and it's how new oceanic crust is created.
Other boundary types:
* Convergent boundaries are where plates collide. This results in one plate being subducted (pushed under) the other, leading to mountain formation, volcanoes, and earthquakes.
* Transform boundaries are where plates slide past each other horizontally. This causes earthquakes but doesn't directly add to the lithosphere.
So, divergent boundaries are the key to the continuous renewal and growth of the Earth's lithosphere.
