Questions 57 to 61 are based on the following passage.
Large animals that inhabit the desert have evolved a number of adaptations for
reducing the effects of extreme heat. One adaptation is to be light in color, and
to reflect rather than absorb the sun’s rays. Desert mammals also depart from the
normal mammalian practice of maintaining a constant body temperature. Instead of
trying to keep down the body temperature deep inside the body, which would involve
the expenditure of water and energy, desert mammals allow their temperatures to rise
to what would normally be fever height, and temperatures as high as 46 degrees Celsius
have been measured in Grant’s gazelles. The overheated body then cools down during
the cold desert night, and indeed the temperature may fall unusually low by dawn,
as low as 34 degrees Celsius in the camel. This is an advantage since the heat of
the first few hours of daylight is absorbed in warming up the body, and an excessive
buildup of heat does not begin until well into the day.
Another strategy of large desert animals is to tolerate the loss of body water
to a point that would be fatal for non-adapted animals. The camel can lose up to
30 percent of its body weight as water without harm to itself, whereas human beings
die after losing only 12 to 13 percent of their body weight. An equally important
adaptation is the ability to replenish this water loss at one drink. Desert animals
can drink huge volumes in a short time, and camels have been known to imbibe (吸
收) over 100 liters in a few minutes. A very dehydrated person, on the other hand,
cannot drink enough water to rehydrate at one session, because the human stomach
is not sufficiently big and because a too rapid dilution of the body fluids causes
death from water intoxication. The tolerance of water loss is of obvious advantage
in the desert, as animals do not have to remain near a water hole but can obtain
food from grazing sparse pastures. Desert-adapted mammals have the further ability
to feed normally when extremely dehydrated. It is a common experience in people that
appetite is lost even under conditions of moderate thirst.
57. What is the passage mainly about?
A) Animals developed different strategies to survive.
B) Large animals can take strategies to reduce the effect of extreme heat.
C) Animals can tolerate the loss of body water.
D) A very dehydrated person can drink enough water to rehydrate.
58. Why light in color is important to large animals in deserts?
A) It helped them maintain a constant normal body temperature.
B) It reflects rather than absorbs the sun-light.
C) It helps them see their peers at night.
D) It helps them keep cool during the night.
59. What will be fatal to non-adapted animals?
A) Keeping a normal body temperature.
B) Drinking polluted water.
C) Drinking huge volumes of water in a short time.
D) Feeding when dehydrated.
60. What does the author imply about desert-adapted mammals?
A) They do not need to eat much food.
B) They can eat large quantities quickly.
C) They easily lose their appetites.
D) They can travel long distances looking for food.
61. What is the following strategy not mentioned by the author?
A) The body temperature can be extremely high and cold.
B) Tolerate the loss of body water and replenish it immediately.
C) Lost appetite under the condition of moderate thirsty.
D) To be light in color.
