1.   As the layers of cells grow, the veins become clogged and cut off the supply of chlorophyll, which makes the leaves look green.

2.   As coastal waters warm in July and August, the marine layer typically grows thinner, allowing morning fog and low clouds to disperse faster.

3.   That layer grows back within days.

4.   The layer has grown even thinner, largely due to ozone-destroying chemicals such as CFCs and halons.

5.   When the outer layer grew back, the cornea retained its corrected shape.