21. The passage implies which of the following about shergottites?
I. They are products of volcanic activity.
II. They derive from a planet larger than Earth.
III. They come from a planetary body with a chemical composition similar to that of Io.
I only
II only
I and II only
II and III only
I, II, and III
22. According to the passage, a meteorite discovered on Earth is unlikely to have come from a large planet for which of the following reasons?
There are fewer large planets in the solar system than there are asteroids.
Most large planets have been volcanically inactive for more than a billion years.
The gravitational pull of a large planet would probably prohibit fragments from escaping its orbit.
There are no chondrites occurring naturally on Earth and probably none on other large planets.
Interbody impact is much rarer on large than on small planets because of the density of the atmosphere on large planets.
23. The passage suggests that the age of shergottites is probably
still entirely undetermined
less than that of most other achondrites
about 3.5 billion years
the same as that of typical achondrites
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