Rocks form in horizontal layers. However, as shown along mountainsides, rock layers can become twisted or bent. The work of James Hutton and Charles Lyell helped to explain observations of twisted or bent rock layers. What was one of their conclusions? A. Earth is extremely old, and Earth processes acted gradually to twist or bend rocks. B. Earth is only a few thousand years old, and Earth formed with many twisted or bent rocks. C. Earth is only a few thousand years old, and Earth processes acted much more rapidly in its early history. D. Earth is extremely old, and Earth formed with many twisted or bent rocks.