Here's a breakdown:

* Lithosphere: This is the rigid outermost layer of Earth, composed of the crust and the uppermost part of the mantle. It's broken into tectonic plates that move around on the asthenosphere.

* Asthenosphere: This layer is located beneath the lithosphere and is part of the upper mantle. It's characterized by being partially molten and having a ductile (flexible) nature. This allows tectonic plates to move on top of it.

Think of it like this: the lithosphere is like the hard shell of an egg, and the asthenosphere is like the gooey yolk underneath. The yolk allows the shell to move around, just as the asthenosphere allows tectonic plates to move.