Lazy Shy Live in a cave Those might not be positive attributes for the average human, but they sure are good for animals trying to survive in a changing environment. According to a new study, beasts that hibernate(冬眠)or crawl into holes are less likely to be listed as endangered than those that don"t. Following up a previous study on extinct animals, which showed that species exhibiting "sleep or hide"(SLOH)behaviors did better than others, the researchers wanted to see if the same was true of modern creatures like moles and bears. To find out if our more timid animals havea leg upin the survival game, researchers made a master list of 443 sleep-or-hide mammals. With their list in hand, the team compared their 443 to the "red list" of endangered species published by the International Union for Conservation of Nature. As suspected, a sleepy or hiding animal was less likely to be on the red list than a regular animal, and a red-list animal was also less likely to be a SLOH-er. This makes a lot of sense, as animals that hide away in a cave or a tree hole are protected by their physical shelters from a variable environment outside, while hibernators enjoy a flexible metabolism(新陈代谢)that can help them adapt to a changing climate. The phrase "a leg up" in Paragraph 2 probably means______.

A. an instinct
B. an advantage
C. a fight
D. a chance