【文章內(nèi)容簡介】 id screen. D A long carrot passing behind a window screen.37 What is the talk mainly about? A Similarities between vision in cats and in humans. B Hunting techniques of cats. C The position of the eyes on the faces of mammals. D Distinctive features of a cat39。s vision.38 What does the professor imply is a popular misconception about cats? A They are able to see in the dark. B They are good hunters. C They rely on smell more than sight for hunting. D They are unable to see in three dimensions.39 What are two areas in which cats39。 visual abilities are better than humans39。 ? Click on 2 answers. A Judging distances. B Seeing images clearly. C Seeing in poor light. D Sensing movement.40 What role does guanin play in the visual processes of a cat? A It causes the cat39。s pupils to dilate. B It reflects light from the cat39。s retina. C It prevents the blurring of images. D It allows the cat to see colors.41 What does the professor say is one way mice are sometimes able to escape detection by cats? A By running through a dimly lit area. B By jumping onto high objects. C By standing still. D By running behind the cat.42 What does the position of the eyes on a cat39。s face help the cat do? A See animals that are not moving. B See objects in poorly lit surroundings. C Judge distances accurately. D Distinguish between shades of color.43 What does the professor mainly discuss? A Plants eaten by desert animals. B The differences between various types of cacti. C Why some desert plants are larger than others. D How plants are able to live in the desert.44 What does the professor say about the seeds of an annual desert plant? A They sprout only under favorable conditions. B They are encased in a very thin shell. C They are attractive as a food source for desert birdsD They can hold a large amount of moisture.45 What are two features of their leaves help some desert plants avoid water loss?Click on 2 answers.A They are covered with a kind of wax. B They reflect sunlight. C They are very small. D They are covered with tiny holes.46 When do the stems of a succulent plant bee enlarged? A When the temperature gets very hot. B When it rains. C When a predator is near. D When the plant is ready to disperse its seeds.47 What does the professor say about the roots of a succulent plant? A They usually grow above the ground. B They can be eaten. C They are close to the surface of the ground. D They are filled with water.48 What are the two primary functions of the sharp spines on a cactus plant? A They prevent animals from eating the plant. B They channel water toward the roots of the plant. C They allow oxygen to be released from the plant. D They attract pollinating insects to the plant.49 What is the talk mainly about? A The diet of whitetailed deer. B Techniques used by predators to catch deer. C Types of shelter found in deer yards. D The use of trails by whitetailed deer.50 Why are the trails of the whitetailed deer important for their food supply? Click on 2 answers. A The deer follow the trails to eat in areas outside the home range. B The deer eat plants growing alongside the trails. C The deer use the trails to travel to their feeding grounds. D The deer build trails around their yards to protect their food supply.51 What is the primary function of runways? A To connect the larger trails in the home range to each other. B To allow deer to move easily to new yards. C To provide a direct route to the deer yard. D To permit several deer to move together along a path.52 What happens to the trail system when food bees scarce in winter? A It is damaged from overuse. B It is expanded. C It is joined with another herd’s trails. D It is abandoned.53 According to the professor, why do the deer need to know the entire network of trails? Click on 2 answers A To enable them to find their yards in bad weatherB To help them guard the boundaries of the home range from other deerC To allow them to escape when pursued.D To assist them in detecting predators in their territory. 54 According to the professor, why is deep snow dangerous for whitetailed deer? A The deer are unable to move quickly through the snow. B Predators can easily conceal themselves in the snow. C The hooves of the deer bee brittle in the cold snow. D The deer cannot see the trail und