medium · Act reading
A coral reef looks like architecture but behaves like a city under perpetual renovation. Each polyp lays down a thread of limestone, then its descendants build atop the abandoned skeletons, so the visible reef is mostly the accumulated past of countless tiny lives. When a heat wave bleaches the surface, the loss is real, yet the structure beneath remains a record—an archive of conditions stretching back centuries. Scientists read these layers the way others read tree rings, extracting from the stone a diary the ocean never meant to keep. In the passage, the comparison of coral layers to 'tree rings' chiefly serves to:
- suggest that coral and trees are biologically related organisms with shared ancestry.
- emphasize that the reef preserves a readable record of past environmental conditions.
- argue that coral reefs grow at exactly the same measurable rate as forest trees.
- prove that heat waves leave no lasting damage on the surface of a reef.
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