Answer:
It involves multiple trials.
Explanation:
Repetition is the "repeating“ (multiple trials) of your own investigation for accuracy.
Answer:
A chromosome is a long DNA molecule with part or all of the genetic material of an organism. Most eukaryotic chromosomes include packaging proteins called histones which, aided by chaperone proteins, bind to and condense the DNA molecule to maintain its integrity
The answer for this question is Scientists understood that species share a common ancestor. so it is letter C. hope that helps