About 90% of our DNA is the same.
Mass is the amount of matter in any object.
This is only explanation. What are the questions for it?
The answer is letter b. adaptation. Adaptation occurs when living organisms adapt to their surroundings or environment over a long period of time. In this case, Dark Furred Squirrels were abundant, since squirrels adapted to the dark shady area they have lived and adapted into a dark furred one, which allowed it to be more common due to adaptation.