Researcher: Over the course of three decades, we kept records of the average beak size of two populations of the same species of bird, one wild population, the other captive. ██████ ████ ███████ ███ ███████ ████ ████ ██ ███ ███████ █████ ███ ███ ███████ █████ ███ ███████ ████ ████ ██ ███ ████ █████ █████████ ██████████████
Why did the average beak size of wild birds shrink while the average beak size of captive birds stayed constant?
Any hypothesis explaining these findings must state a difference between the birds in the wild and the birds in captivity that explains why the beaks of the wild birds apparently shrunk. It may be a physical difference between the bird populations or it may be a difference in the way the birds were apprehended and measured.
Which one of the following, ██ █████ ████ █████ ██ ███████ ███ ████████████ █████████
The small-beaked wild █████ ████ ██████ ██ ███████ ███ ███████ ████ ███ ████████████ ████ ██████
The large-beaked wild █████ ████ ██████ ██ ███████ ███ ███████ ████ ███ ████████████ ████ ██████
Changes in the ████ ██████ ████ ██████ ██████ ███ █████ ██████ ███████ ███ ████████ ██ ████████████ █████ ████ ████████████ ██████
The average body ████ ██ ███ ███████ █████ ████████ ███ ████ ████ ███ █████ ███████
The researcher measured ███ █████ ██ ████ ██ ███ ████ █████ ██ ████ ████ ███ █████████