C. are sensitive to significant variations in temperature.
D. closely resemble lions as regards size, speed and strength.
20. As is pointed out in the passage, a flat terrain ____.
A. is usually the favoured habitat of the tiger. B. rather than rocky cliffs gives tigers better opportunities for hiding.
C. provides camouflage for leopards.
D. is usually wet, so tigers prefer higher levels.
21. From the passage we infer that contrary to what is generally thought, ___.
A. once a prey starts to move a tiger can rarely catch it.
B. hearing is the least developed sense of the tiger
C. the leopards hunting ability is far behind that of the tiger.
D. is not the one that welcomes change Scientists have long sought ways to define and measure human intelligence. And while
theorists of intelligence have grown more sophisticated since the 1800s when some believed
mental ability were determined by the size of the person's head. Researchers still do not agree
about certain fundamental principles of human thought. They hence continue to debate such
basic questions as whether heredity or the environment is more important in forming
intelligence.
22. As we infer from the passage, the age-old controversy about whether intelligence depends
upon heredity or the environment…………
A. is now being ignored as it is seen to be fruitless.
B. was finally reached in area 1800.
C. has only recently become a subject for serious research.
D. does not seem to have ceased yet. 23. In accordance with the passage, in the early nineteenth century, some people held the view
that a person's mental capacity ___.
A. could never be changed.
B. depended on the head size: C. was purely hereditary.
D. was completely shaped by the environment.
24. One may infer from the passage that a full understanding of the nature and the capacity of
human intelligence ___.
A. can only be achieved by exceptionally sophisticated minds .
B. has finally been achieved by modern scientists .
C. is sure to be realized within the next few years .
