In each of the following sentences, choose the appositives and interrupters that should be set off by commas.
For help with this exercise, see chapter 35 of Real Essays 5e.
Example
Thousands of “snowballs” from outer space are hitting Earth’s atmosphere every day according to scientists at a recent meeting of the American Geophysical Union in Baltimore.
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Over billions of years they reported this bombardment of cosmic slush has added vast amounts of water to Earth’s atmosphere and oceans.
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These extraterrestrial snowballs made up of ice and cosmic dust may have played a key role in nurturing life on this planet and perhaps elsewhere in the solar system.
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They are about forty feet in diameter the size of a small house.
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These small, cometlike objects unlike large comets are extremely hard to see because they break up into fragments and then vaporize.
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Astronomers and physicists however have speculated about their existence since 1986.
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Dr. Louis A. Frank a physicist at the University of Iowa first theorized about them to explain the dark spots he observed in images of Earth’s sunlit atmosphere.
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Dr. Frank noticed these spots or atmospheric holes while analyzing data from NASA’s Dynamics Explorer 1 satellite.
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NASA’s Polar satellite a veteran space explorer produced more detailed images of these atmospheric holes.
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Many scientists now believe that these snowballs are hitting Earth’s outer atmosphere at an incredible rate of five to thirty a minute or up to 43,000 a day.
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