Regolith is the surface on a planet like the Moon or Mars. It is kinda cool to learn about because if you have not learned about it I would if I was you.
Mars has a red colored surface witch comes from the iron rich mineral in the soil. If you have looked at Mars you can see some gray spots witch is the bare rock showing. Some people think that there was water and maybe even life. They also want to try and have people live there.
The Moon has a smooth surface and has craters. Some people think that the moon is made of the same gases and materials.