Why do astronomers think Earth ended up with so little CO2 compared with Mars and Venus?
A. Volcanoes on Earth outgassed less CO2 than on Venus and Mars.
B. Pollution on Earth has reduced the amount of CO2 originally present.
C. Plant life and abundant water have removed most of the CO2, locking it into rocks and the oceans.
D. Comets striking the surfaces of Venus and Mars added CO2 to their atmospheres, but not to Earth.
Answer: C
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Which one of the following is TRUE?
A. Irregular galaxies rarely have star formation taking place in them. B. Most galaxies appear to be approaching the Milky Way Galaxy. C. Most elliptical galaxies contain only young stars. D. Smaller galaxies called dwarf galaxies tend to be found around larger galaxies like the Milky Way. E. Galaxy collisions destroy most of the stars in the galaxies involved.
What would happen if you had a car made completely of plastic, with no metal parts, and you drove over a vehicle sensor embedded in the road surface?
A. The circuit would detect the absence of magnetic flux, thereby working normally B. The sensor would signal with the opposite polarity, indicating you've already gone through the intersection C. The sensor would not notice you or your vehicle, and you'd be stuck at the red light D. You would overload the sensor, so this is an excellent method for forcing all lights to turn green
According to models of galaxy formation, which population of stars formed first?
A.) The spheroidal population. B.) The disk population. C.) The irregular population. D.) The elliptical population. E.) All stars are about the same age.
Which of the following correctly describes the meaning of albedo?
A) The lower the albedo, the more light the surface reflects, and the less it absorbs. B) The higher the albedo, the more light the surface reflects, and the less it absorbs. C) The higher the albedo, the more light the surface absorbs. D) The higher the albedo, the more light the surface emits. E) The higher the albedo, the more light the atmosphere absorbs.