Which of the following statements best demonstrates gene flow?
To increase genetic diversity, zoos frequently exchange animals for breeding purposes rather than mating animals from the same zoo.
Prior to the industrial revolution, light colored moths were better adapted to survive. After the increased pollution, the number of dark moths increased.
A mutation within a population of giraffes allows for increased variation in neck length.
Over-hunting of the Northern elephant seals has reduced genetic variation in the seal population.