EARTH SCIENCE
TECTONICS
Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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meters
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millimeters
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centimeters
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kilometers
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Detailed explanation-1: -The two continents are moving away from each other at the rate of about 2.5 centimeters (1 inch) per year. Rift valleys are sites where a continental landmass is ripping itself apart. Africa, for example, will eventually split along the Great Rift Valley system.
Detailed explanation-2: -Earth’s land masses move toward and away from each other at an average rate of about 1.5 centimeters (0.6 inches) a year. That’s about the rate that human toenails grow!
Detailed explanation-3: -It is made up of the crust and the solid, uppermost mantle. Continents move apart or come together at speeds of a few centimeters per year.
Detailed explanation-4: -A second problem was that Wegener’s estimate of the speed of continental motion, 250 cm/year, was implausibly high. (The currently accepted rate for the separation of the Americas from Europe and Africa is about 2.5 cm/year). Furthermore, Wegener was treated less seriously because he was not a geologist.
Detailed explanation-5: -Because tectonic plates move very slowly-only a few centimeters per year, on average-it takes a long time to observe changes. Scientists have found that the planet’s continents will likely again be joined together in about 250 million years.