Answer:
Survival of the fittest
Explanation:
Natural selection basically means survival of the fittest- the best, most desirable traits are passed on to next generations. Since the foxes have become faster and faster this would mean that the slower rabbits would end up being eaten. Now that the slower rabbits are out of the gene pool no slow genes would be passed on. Only the faster rabbits are left, therefore fast rabbits are mating with fast rabbits causing the fast gene to be passed on.
