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structure and function

325

I took this photo at the beach. Looking at the tire tracks made me think about why car tires have treads, instead of being smooth, like racing tires. Why?

389

This Praying Mantis has three simple eyes in the center of its face, and two large, compound eyes. What are the two black dots on the compound eyes?

392

I took this photo near the entrance to Arches National Park. What geologic structure shaped the rocks of this park?

398

This is Carlsbad Caverns. What are the main chemicals involved in the formation of all of those beautiful, flowstone structures?

404

This is Oak Tree House at Mesa Verde National Park, built by Native Americans in the year 1250 A.D. They left no written records, and no verbal history survived, so how do we know so precisely when it was built?

410

This photo is downriver from the dam on the Colorado River at Page, Arizona. Both the dam and the bridge support are curved. Why?

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