describe what results when a supernova triggers the creation of chains of star-forming regions
propose a modification in the most widely accepted theory of spiral-galaxy structure
compare and contrast the roles of clouds of gas and dust in two theories of spiral-galaxy structure
describe a new theory of spiral-galaxy structure and contrast it with the most widely accepted theory
describe a new theory of spiral-galaxy structure and discuss a reason why it is inferior to the most widely accepted theory
8. The passage implies that, according to the new theory of spiral-galaxy structure, a spiral galaxy can be created by supernovas when the supernovas are
producing an underlying density wave
affected by a density wave of spiral form
distributed in a spiral pattern
located in the central plane of a galaxy
located in a differentially rotating galaxy
9. Which of the following, if true, would most discredit the new theory as described in the passage?
The exact mechanism by which a star becomes a supernova is not yet completely known and may even differ for different stars.
Chains of star-forming regions like those postulated in the new theory have been observed in the vicinity of dense clouds of gas and dust.
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