题干

对纯合黄色圆粒豌豆和绿色皱粒豌豆杂交实验结果的叙述中,错误的是(   )

A:F1能产生4种比例相同的雄配子

B:F2中圆粒和皱粒之比接近于3∶1,与分离定律相符

C:F2重组类型占5/8

D:F2出现4种表现型的个体,且比例为9∶3∶3∶1

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答案(点此获取答案解析)

C

同类题3

阅读下列短文,从每题所给的A、B、C和D项中,选出最佳选项。

      When one of your car tires goes flat, there are two things you can do, you can complain and change it or, if you don't have a spare, stand helplessly beside the road and hope someone comes to your rescue. Now comes a third choice, called Quick wheel. It is designed to get disabled motorists rolling again as quickly as possible.

      Quick wheel is basically a tiny emergency trailer-complete with three tough little wheels of its own-that supports the flat tire and enables the motorist to drive to a service station without losing much time or expending much energy. The product is made in the Netherlands but is owned and marketed by a US company, Quick wheel Inc. of Greenwich, Connecticut. According to the firm's president, Robert Bockweg, the product meets each of the major worries that customers relate with flat tires: safety, lost time and physical labor.

      To use it, motorists simply unfold the product to its fully extended position, set it in front of the disabled tire, drive the car onto the Quick wheel's ramp(斜板) and fix a special safety strap over the tire. The tire is then locked, or cradled, in Quick wheel's metal frame. Its three wheels do the rest of the work. According to Quick wheel Inc, its product can be driven "for miles" at the speed of up to 45 miles per hour "without any noticeable change in the vehicle's braking (车辆刹车) or steering operation". The company also says that it can be used on just about any type of car, jeep, mini-van or trailer (拖车).

      Bockweg says that Quickwheel will be sold first in the United States, at a price of $150. Sales agreements now being talked over should make the product ready for use in Japan, Canada and Western Europe in the near future. (words: 314 ; time :5ms)