E) The wind blows because of marmot flatulence. Feedback: Heating near the equator causes pressure differences that drive the winds. On a rotating body, whether a flat merry-go-round or a spherical Earth, the rotation causes flows to curve . And very very very little of the wind is traceable to marmots. Points Earned: 1.0/1 .0 Correct Answer(s): C 13. You watched online as Dr. Alley carved a sand canyon with his finger. Based on what you saw, and on what you know about slopes, stability, mass movement, etc., if a landslide happened someplace last week, you would tell the neighbors:
A) All is safe now; nature relieves stress and removes instabilities, and that is what the landslide did. B) Run for your lives! Landslides are always followed by floods and more landslides. C) Care is required; landslides are removing instabilities and moving things towards stability, but a second landslide, or a flood, or other problems are real possibilities. D) Run for your video cameras! Landslides are invariably followed by professors sticking out fingers, and you can get footage to win megabucks on America’s Funniest Classroom Videos. E) Special care is required; landslides invariably trigger earthquakes. Feedback: When Dr. Alley made a “landslide”, others often followed, but not always. Similar behavior is often observed in nature. The Gros Ventre slide near the Tetons dammed a river, with dam failure later releasing a flood, but a flood was avoided at Hebgen Lake outside of Yellowstone. And so far, we don’t think that America’s Funniest Classroom Videos is handing out megabucks. But let us know if they start. Points Earned: 1.0/1 .0 Correct Answer(s): C 14. In the photo above, Sam Ascah is standing on sand and gravel in a pothole, where a stream swirls during the short but intense thunderstorms of Zion National Park. And next to that stream, the other picture shows the sandstone and the hang-on-so-you-don't-fall-over-the-cliff chain along the trail. A likely interpretation of these features is: A) The Park Service carefully cut little grooves behind the chain before they hung it, so that it would look cute and slide well, and they cut the potholes so that hikers would have something to look at. B) The stream swirled rocks around and cut the potholes, and even bounced up the cliff to cut the notches behind the chain.
C) The grooves behind the chain have been cut over decades by motion of the chain as hikers grabbed it, and the potholes were cut by water swirling rocks around during the rare floods over much longer times. D) The potholes and the grooves behind the chain were gnawed by giant beavers. E) The potholes and the grooves behind the chain were gnawed by giant marmots. Feedback: The chain really has hung there for decades, and has been scraped against the cliff dozens of times per day each summer, slowly wearing into the easily broken sandstone. The stream does swirl rocks around and slowly wear down the potholes. The potholes were there beside the cliff when the trail was established, and haven’t changed too much over decades. Points Earned: 1.0/1 .0
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