This trait changes seasonally in captive polar bear populations due to Chlorella (“klor-eh-lla”) and Scenedesmus (“SEEN-ee-des-muss”) growth within enclosure swimming pools. In a case study of natural selection by Hopi Hoekstra, this trait diverged in two rock pocket mouse populations (10[1])in New Mexico following a volcanic eruption. (10[2])Input from U-shaped pupils and dermal (10[1])opsins allow one class of animals to determine how this trait should be modified. (10[1])After exposure to UV, (10[1])certain mammalian cells express (-5[1])tyrosinase to release the “eu-” and “pheo-” forms of a molecule that controls this trait. (10[1])Melanocytes control this trait in mammals, (10[1])whereas (10[1])other animal species alter this trait through the activity of chromophores. For 10 points, name this trait that can be changed by cuttlefish and chameleons for adaptive camouflage. ■END■ (10[1])