jay4clout12 jay4clout12 10-09-2021 Biology contestada In this lab, the three flocks of birds changed in numbers between generation 1 and generation 3. Why? Check all reasons. The amount of food available increased and decreased. If a flock’s beak type made it easier to pick up the available food, the flock grew. If a flock’s beak type made it harder to pick up the available food, the flock shrunk.