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One advantage of breeding African　bees with other bee types (Africanization) may be resistance to the parasitic mite Varroa jacobsoni, a major threat to modern beekeeping. In parts of Europe, this mite is devastating honeybees and killing many colonies despite preventive measures by beekeepers. But in Brazil Varroa jacobsoni has been present in Africanized bees since 1972 without the loss of a single colony,even though beekeepers there undertook no preventive measures. The mites lay eggs within the brood cells of immature bees, and developing mites feed on the hemolymph (blood) of bee pupae. But fewer mites reproduce in Africanized bees than in European bees. Some researchers point out that this resistance may be related to the Africanized worker bee's shorter development period, which prevents some mites from reaching maturity. Recently the mite has become a serious problem in colonies of European bees in North America. Africanization of these bees may be the best safeguard against this parasite.

The passage suggests that which of the following was true of the honeybee colonies described in line 4-6?
A.Their life expectancy, when free of disease, was shorter than that of European bee colonies in North America.
B.They were not Africanized.
C.Their life cycle did not accommodate the feeding habits of Varroa jacobsoni.
D.They responded well to measures to control Varroa jacobsoni.
E.They were managed using methods that were more modern than those employed in Brazil.

The author cites all of the following as evidence that Africanized bees’resistance to Varroa jacobsoni is superior to that of European bees EXCEPT:
A.Fewer Varroa jacobsoni mites reproduce in Africanized bees.
B.Varroa jacobsoni is killing many bee colonies in Europe.
C.Beekeepers in Brazil have not used preventive measures to protect their colonies.
D.Brazilian bee colonies have endured Varroa jacobsoni since 1972.
E.At least some European bee colonies have been saved by preventive measures.

According to the passage, research suggests that one possible reason the Africanized bees in Brazil have successfully resisted Varroa jacobsoni is that
A.the life cycle of the Africanized bee may limit the Varroa jacobsoni mite's opportunity to reach full development
B.the Africanized bees may have had an opportunity to develop a chemical resistance to Varroa jacobsoni
C.the location of bee colonies in Brazil may provide a natural deterrent to Varroa jacobsoni
D.Varroa jacobsoni may be relatively new to Brazil and may not have had time to become widespread
E.beekeepers may have developed effective control techniques for Varroa jacobsoni

The author's argument regarding the resistance of Africanized bees to Varroa jacobsoni would be most weakened if which of the following were true?
A.The bees in Brazil were resistant before being Africanized.
B.The number of bee colonies in North American increased dramatically whereas the number in Brazil remained unchanged.
C.Mites found in European bees reproduce at a faster rate than mites of identical species found in the bees in Brazil.
D.Africanized bees retain many of the characteristics of European bees.
E.Bee colonies in Europe continue to produce greater quantities of honey than do those in Brazil.

参考答案

正确答案:B E A C