instruction:
You are given a sentence and your task is to generate another sentence that supports the given input.
question:
A caldera is formed when magma flows out of a volcano, leaving an empty chamber that collapses.
answer:
After a massive eruption, a mountain collapsing above an empty chamber will create a caldera.

question:
According the law of superposition, we assume that the rock unit located on the bottom is older than the top layer.
answer:
Deeper layers of rock must be older than layers closer to the surface, this is the law of superposition.

question:
For example, the element carbon is in diamonds, used for jewelry, and in graphite, used in pencil lead.
answer:
Although they differ vastly in hardness, pencil lead and diamonds both contain carbon.