Why are there more fat, shaggy bison in Time 3 than in Time 1?
A. The snowy winter made the smaller, smooth bison grow longer
fur. The next year, all the bison grew longer fur and got fat.
B. The small, smooth bison moved to a warmer place for winter.
The next year, most of the bison were the fat and shaggy ones
that didn't move away.
C. After the snowy winter, the smaller, smooth bison started to have
shaggy offspring. The shaggy offspring do better in cold weather.
D. During the snowy winter, the fat, shaggy bison survived while
most of the other bison died. The next year, the shaggy bison
produced mostly shaggy offspring.