11.5

1. Listen to Track 90.
  
  Now answer the questions.
2. What does the professor mainly discuss?
  1. When and why some animals engage in hibernation or torpor
  2. Animal defense mechanisms in cold climates
  3. The navigation techniques of species that migrate
  4. Hormonal shifts that control an animal’s internal calendar
3. According to the professor, why do smaller mammals typically hibernate rather than migrate?
  1. They are more likely to be caught by predators if they migrate.
  2. They are skilled at building underground dens.
  3. They are less likely to find food if they migrate.
  4. They need less energy to stay warm than to travel long distances.
4. In order to determine whether an animal is in a state of hibernation or torpor, which of the following questions needs to be answered?
  1. Whether the animal is large or small
  2. Whether the act is voluntary or involuntary
  3. The amount of food available
  4. The current weather conditions
5. According to the professor, what are two triggers that determine when an animal enters into or awakens from hibernation? Choose 2 answers.
  1. Food availability
  2. Hormonal shifts
  3. Length of the day
  4. Snowstorm frequency
1. Listen to Track 91.
  
  Now answer the question.
2. What does the professor mean when she says this?
  1. She has already covered the details in an earlier class.
  2. She is not confident enough about the details to explain them.
  3. She does not want to discuss details that are not relevant to her main point.
  4. She believes that the explanation is too complicated for the students to understand.
4. 1. Listen to Track 92.
    
    Now answer the question.
  2. What point does the professor make when she says this?
    1. It is not clear how animals know whether to hibernate or migrate.
    2. Different animals hibernate at different times of the year.
    3. The changing temperature might prevent animals from migrating.
    4. Animals might hibernate at the wrong time if they only use weather signals.