Geological time is divided into units based upon types of...?

A) Sedimentary Rocks

B) Climate Changes

C) Organisms

D) Igneous Rocks

4 Answers

  • Elmyr
    Lv 7
    1 decade ago
    Favorite Answer

    A. Sedimentary rocks. Organisms is not correct.


    Jurassic is named for the Jura Mountains of France. The Jurassic was when the limestone of the mountains formed.

    Cretaceous is from the chalk deposits of the Baltic and S. England.

    For the sedimentary rocks that every period is named for see:

  • 1 decade ago

    The answer is C.

  • Anonymous
    1 decade ago


  • Anonymous
    5 years ago


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