The author resolves the question of whether heat pumps run counter to the principle of energy conservation by ______.
A. carefully qualifying the meaning o{ that principle
B. pointing out a factual error in the statement that gives rise to this question
C. supplying additional relevant facts
D. denying the relevance of that principle to heat pumps.
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Which of the following statements about the salinity of a body of water can best be inferred from the passage？
A. The temperature of the water is the most important factor.
B. How quickly the water moves is directly related to the amount of salt.
C. Ocean salinity has little effect on sea life.
D. Various factors combine to cause variations in the salt content of water.
David Lack' s research contributed to biological science specifically in the area of______.
A. Evolution
B. mating behavior
C. animal demography
D. immunology
According to the passage, the ocean generally has more salt in ______.
A. coastal areas
B. tropical areas
C. rainy areas
D. turbulent areas
Which of the following is NOT mentioned in the first as a reason for popular interest in birds？
A. Their ecological value.
B. Their appealing habits.
C. Their visibility.
D. Their beauty.
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