Why are astrologers not considered to be scientists?Astrologers do not use tools.Astrologers do not observe the universe.Astrologers do not use the scientific method.Astrologers do not go to college.

The answer is:  [C]:  "Astrologers do not use the scientific method." 
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Note:  Choice [A] is incorrect.  Astrologers do use tools.
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Choice [B] is incorrect.  Some astrologers do observe the universe.
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Choice [D] is incorrect.  Astrologers may or may not go to college; and whether or not they do or do not is irrelevant as regard to whether to they are considered "scientists".
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