Alice is curious whether her pet iguana is more attracted to brightly colored insects or those with drab colors. she gets 20 drab-colored insects of the same species from the pet store and marks 10 of them with a red paste. all 20 insects are released in her iguana's tank at the same time, and she observes the lizard's response. after five minutes, alice notes that her iguana ate all of the marked insects and only 2 of the unmarked insects. she concludes that her iguana prefers brightly colored insects over those with drab colors. what is another possible explanation for these results?