Bergmann's and Allen's rules explicitly predict which of the following?
a) Animals will be long and lean in warm climates and stocky in cold climates
b) Animals will not have much fur or feathers in warm climates, and lots of fur or feathers in cold climates
c) Animals will be darker-colored in warm climates, and lighter-colored in cold climates
d) Animals will be vegetarian in warm climates, and meat-eating in cold climates