How can we use rocks to determine how an area used to look in the past?

One of the best ways to use rocks to determine past geography is to look at water lines. Many cliffs contain "stained" waterlines on the surface of the rocks, which shows that water at a certain level used to occupy that area.

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Cell division is important to single celled organisms because it allows the cells to reproduce. through cell division, cells make exact copies of themselves. when single celled organisms go through cell division, they make exact copies of themselves which is how they reproduce.