Sedimentary rock layers contain information about the relative ages of events and objects in Earth's history. As you read earlier, sedimentary rocks form from the sediments that fall to the bottom of lakes, rivers, and seas. Over time, the sediments pile up to form horizontal layers of sedimentary rocks
The rock layers above the bone bed are younger than the bone bed. The rock layers below the bone bed are older than the bone bed.
<span>Secondary succession in healthy ecosystems following natural disturbances often reproduces the original climax community. Ecosystems may or may not recover from extensive human-caused disturbances.</span>
