Why might different types of fossils be found in rock layers that come before and after a rock layer that contains no fossils?

because they can move around under the earth

Explanation:

periodic trends is an atom that gets larger as the number of electronic shells increase, the radius of atoms increases as you go down a certain group in the periodic table of elements. in general, the size of an atom will decrease as you move from left to right of a certain period.

b.

the accuracy of the data.