Answer:
You take any of the "signs of change in populations of organisms and their environments". For imagine, Australopithecus (early man) turning to Homo sapiens. In that way they could tell that you took this journey.
Answer:
well theory is ranked second highest in certainty in scientific nomenclature. theory dictates it is more certain of a principle than a hypothesis yet not concrete enough to be a law. examples are the theory of evolution versus the law of gravity
Tumor cells are cells that divide relentlessly, forming solid tumors or flooding the blood with abnormal cells.