[简答题]When can procedures subjecting animals to distress be used

[简答题]When can procedures subjecting animals to distress be used

[简答题]Questions 30-39 The response of most animals when suddenly faced with a predator is to flee. Natural selection has acted in a variety of ways in different species to enhance the efficacy of the behaviors, known as “ flight behaviors” or escape behaviors, that are used by prey in fleeing predators. Perhaps the most direct adaptation is enhanced flight speed and agility. Adaptations for speed, however, are likely to require sacrifices in other attributes, so we might expect only some species to adopt a simple fast flight strategy. Another way of enhancing the effectiveness of flight is to move in an erratic and unpredictable way. Many species, like ptarmigans, snipes, and various antelopes and gazelles, flee from predators in a characteristic zigzag fashion. Rapid unexpected changes in flight direction make it difficult for a predator to track prey. In some species, like the European hare, erratic zigzag flight might be more effective in the presence of predators that are faster than t
A. A．encourage
B．resist
C．increase
D．reveal

[单项选择]Some animals apparently can resist cancer by strengthening their immune system in preparation for winter, Johns Hopkins researchers said on Wednesday.
The scientists said their study is the first to show that the central nervous system, reacting to environmental changes, may spark changes in the body’s immune system that control the growth of tumors.
They said if that is the ease, a better understanding of how the process works eventually could lead to new cancer treatments.
Dr. Randy Nelson, an associate professor of psychology at Hopkins, stressed at a meeting of the Society of Neuroscience that further study would be needed to confirm a connection between the length of the day, the animals’ immune system and cancer. More work also would be needed to show that the findings could be applied to human cancer.
Dr. Faye Austin, an immunologist with the National Cancer Institute in Bethesda, said: "It’s a very intriguing observation that the length of exposure t
A. the findings of animals’ resistance to cancer can be applied to human cancer treatments
B. the length of exposure to light can affect the growth of a tumor
C. there is a relation between the length of the day, the animals’ immune system and cancer
D. there is a new approach for studying the function of central nervous system in the body’s immune system

[填空题]Animals can be made to do both when the activity of certain genes is doubled.

[填空题]

What can the animals live on
These animals can live on （）