Why do rocks tell scientists about the environment in which they formed?

Sedimentary rocks tell us about past environments at Earth's surface. Because of this, they are the primary story-tellers of past climate, life, and major events at Earth's surface. Each type of environment has particular processes that occur in it that cause a particular type of sediment to be deposited there.

Explanation:

Because some have fossils from long ago and some have dirt or sand in them that has hardened into rock over the years if that makes since?

Explanation:

Like if it's sand it could have been a sand dune or desert but if its dirt it could been a grassland or forest?