10 points
after darwin proposed his ideas about natural selection as a mechanism for evolution, it took time before evolution was generally considered a theory. why do we now refer to it as a theory?
a. fewer scientists agree with darwin's ideas now than they did at first, so it is called a theory.
b. questions still remain concerning its validity, so it must be called a theory. c. enough supporting evidence has accumulated for it to be called a theory.
d. the meaning of the word 'theory' has changed since darwin's time, and it fits the new meaning.