单项选择题

According to the explanation given in the passage, which of the following causes superbubbles to gradually assume the shape of a chimney

A． The gravitational attraction of supernovas adjacent to the region of the chimney' s formation
B． The effect of entropy on the relative abundance of hot interior gas within the superbubble
C． A chemical reaction involving ionized trace ions at the heart of the superbubble
D． A tendency toward coalescence in the gases that contribute to the formation of the superbubble
E． A natural buoyancy of the superbubble, which causes the chimney to stretch and become a gaseous conduit
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单项选择题
The author of the passage believes that the Neuromancer trilogy would have been improved had Gibson
A． chosen to focus less on the limits on the traditional view of the body as a laboring device
B． treated in greater depth the epistemological systems of laborers whom he admires
C． represented alternative models of labor without qualifying them with costs
D． used characters who succeed in realizing how they are marked by machinery
E． elaborated more fully concerning the models of labor that are dominant over his current models
单项选择题
Which of the following, if true, would most seriously undermine the validity of the model of star formation that is presented in the passage
A． A star is discovered that emits lower levels of trace ions than those discovered by x-rays of our galaxy's sun.
B． A section of the universe is discovered to lack both stars and any sort of interstellar medium.
C． A galaxy is discovered with a negative rate of star formation.
D． In one corner of the galaxy, coronal gas is discovered to rarify as it becomes cooler.
E． A superbubble is found of equal mass to the galaxy surrounding it.
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