What is geologic time? A)a unit of time used to measure rock formation

B)the timne that has passed since Earth formed

C)the period before humans appeared on Earth

D)a period of time during which only rocks existed

evidence and logical support is essential for a scientist to do in order to maintain credibility. this is because no one can believe without any logic and without any evidence.hence a scientist can maintain credibility by proving himself and by answering logically so experiments prove very beneficial. logical hypothesis give conclusion which is acceptable. therefore, there are two main factors to maintain credibility by a scientist is evidence and logical support.

well, i believe that the answer is 2. : 3