Which of the following statements is true about increased intake of vitamin D？
A. It can"t help to reduce the risk of getting cancer.
B. It can control the expression of genes regulating cell division.
C. It has been recommended specifically for cancer prevention.
D. It is good to intake vitamin D as much as possible.
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According to the ecology method, the growth of Scandinavian wolves
A. has failed to attain the estimated number.
B. has been severely affected by various reasons.
C. has been underestimated during the past decade.
D. has helped researchers to locate the extent of poaching.
Which of the following may discourage the buyers of electric vehicles？
A. Driving range on one charge.
B. Noise of operation.
C. Acceleration speed.
D. Cost on maintenance.
Why do drug companies make no effort on the study of RAS？
A. Because they can"t find how medicine can take effect on RAS.
Because RAS is often mutated and changes forms.
C. Because it doesn"t seem to be of vital importance on treating cancers.
D. Because RAS binds firmly with cells and are inseparable.
The phrase "the palace intrigue"(Line 1, Para.6)most probably means
A. the internal plot.
B. the history of a company.
C. the foundation of company.
D. the internal story.
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