Why were mutations needed for the species of moth to survive during the Industrial Revolution in London? Explain how this mutation lead to the evolution of this species of moth.

If the moths were to not mutate, then they'd die off.

Explanation:

If I do recall, they changed color didn't they. they went from a bright white to Ash brown. well they were bright white so that they could blend in with the trees, but then pollution caused the tree to die, or at least change color. the moths were then being hunted by predators, except the dark ones. so because of natural selection and mutation the rest of the moths were of dark color. When the factories were shut down the trees came back, all white. causing the same thing to happen but this time the white moths thriving.