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Unformatted text preview: of the Sun? ○ To test the effect of light on the birds' restlessness
○ To test whether birds were using the Sun to navigate
○ To simulate the shifting of light the birds would encounter along their regular migratory route
○ To cause the birds to migrate at a different time than they would in the wild
6. According to paragraph 3, when do caged starlings become restless? ○ When the weather is overcast
○ When they are unable to identify their normal migratory route
○ When their normal time for migration arrives
○ When mirrors are used to change the apparent position of the Sun
Paragraph 4 在 So, in another set of experiments, Kramer put identical food boxes around the cage, with food in only one of the boxes. The boxes were stationary, and the one containing food was always at the same point of the compass. However, its position with respect to the surroundings could be changed by revolving either the inner cage containing the birds or the outer walls, which served as the background. As long as the birds could see the Sun, no matter how their surroundings were altered, they went directly to the correct food box. Whether the box appeared in front of the right wall or the left wall, they showed no signs of confusion. On overcast days, however, the birds were disoriented and had trouble locating their food box. 7. Which of the following can be inferred from paragraph 4 about Kramer s reason for filling one food box and leaving the rest empty? ○ He believed the birds would eat food from only one box.
○ He wanted to see whether the Sun alone controlled the birds' ability to navigate toward the box with food.
○ He thought that if all the boxes contained food, this would distract the birds from following their migratory route. ○ He needed to test whether the birds preferred having the food at any particular point of the compass.
Paragraph 5在In experimenting with artificial suns, Kramer made another interesting discovery. If the artificial Sun remained stationary, the birds would shift their direction with respect to it at a rate of about 15 degrees per hour, the Sun's rate of movement across the sky. Apparently, the birds were assuming that the "Sun" they saw was moving at that rate. When the real Sun was visible, however, the birds maintained a constant direction as it moved across the sky. In other words, they were able to compensate for the Sun's movement. This meant that some sort of biological clock was operatingand a very precise clock at that. 8. According to paragraph 5, how did the birds fly when the real Sun was visible? ○ They kept the direction of their flight constant.
○ They changed the direction of their flight at a rate of 15 degrees per hour.
○ They kept flying toward the Sun.
○ They flew in the same direction as the birds that were seeing the artificial Sun
9. The experiment described in paragraph 5 caused Kramer to conclude that birds possess a biological clock 335
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This note was uploaded on 09/17/2013 for the course LANGUAGE 13DL208 taught by Professor Wang during the Fall '13 term at East China Normal University.
- Fall '13