题干

果蝇中,红眼(B)与白眼(b)是由一对等位基因控制的相对性状,白眼雄蝇与红眼雌蝇杂交,F1全为红眼,F2代白眼:红眼=l:3,但是白眼只出现于雄性,下列叙述正确的是(  )

A:实验结果不能用盂德尔分离定律解释

B:从上述结果就可判断该基因仅位于X染色体上,Y上无等位基因

C:将F2中白眼雄蝇与红眼雌蝇杂交,每一组杂交都可获得白眼雌蝇

D:要确定该基因是否仅位于X染色体上,应将白眼雌蝇与红眼雄蝇杂交

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D

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    A study shows that one million lives might be saved each year if people wash their hands with soap(肥皂) often. It also says that hand-washing with soap could be among the best ways to reduce diseases. Doctors say many diseases can be prevented from spreading by hand-washing. These include the common cold, influenza(流行感冒), hepatitis(肝炎), infectious diarrhea(腹泻) and so on.

    Doctors say you are easy to catch a cold by touching your nose or eyes after someone nearby has sneezed or coughed. Another reason to catch a disease is to eat food prepared by someone whose hands were not clean.

    They also say that hand-washing is especially important before and after preparing food, before eating and after using the toilet, after touching money and sneezing or coughing. The most helpful way is to wash them together while using soap and warm water. You do not have to use special soap. Be sure to wash all areas of the hands for about ten to fifteen seconds.

Title : Basic Knowledge of hand-washing

Diseases are

under ____.

People can____ many diseases from spreading by hand-washing such as the common cold, influenza and so on.

The____ of

becoming sick.

●Touch your nose or eyes after someone nearby has sneezed or coughed.

●Eat food prepared by____ hands.

____to do hand-washing.

●Before and after preparing food.

●Before eating and after using the toilet.

●After touching money and sneezing or coughing.

How to do

hand-washing.

●Wash them together while using soap and warm water.

●Wash all areas of the hands for about 10-15 seconds.