The reason for the increase is that the light-colored moths are no longer "selected against" by predators. These birds could only see the light ones against a sooted background. After removing the dark soot, these predators could no longer distinguish the light ones from their natural light background. Thus more light-colored moths survived to reproduce, passing on more of their recessive genes for light color to their offspring. After several hundreds of generations, most of the later generations were light, due to selective advantage of camouflage to survive predation.
The RNA sequence comparison
The two main items that are traded in Ghana are gold and salt. The correct answer is A.