Official 42 Lec 2
Question 3 of 6
Why does the professor emphasize the number of clusters mapped by Abell?

A.

To help explain why Abell's classification scheme was widely adopted

B.

To explain why Abell was the first astronomer to notice spiral-shaped galaxies

C.

To provide evidence that Abell’s method of surveying galaxies was superior to that used for previous surveys

D.

To show how much Abell relied on earlier research

正确答案:A

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