题干

已知玉米籽粒黄色对红色为显性,非甜对甜为显性。纯合的黄色非甜玉米与红色甜玉米杂交得到Fl,Fl自交或测交,预期结果不正确的是(   )

A:自交结果中黄色非甜与红色甜比例9∶1

B:自交结果中黄色与红色比例3∶1,非甜与甜比例1∶1

C:测交结果为红色甜∶黄色非甜∶红色非甜∶黄色甜为1∶1∶l∶l

D:测交结果为红色与黄色比例1∶1,甜与非甜比例1∶l

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答案(点此获取答案解析)

B

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根据短文内容,从短文后的选项中选出能填入空白处的最佳选项。选项中有两项为多余选项。

    Many people think of guys as being carefree when it comes to their appearance. But in fact, a lot of guys spend plenty of time in front of the mirror. They care just as much as girls do about their body image.

    Body image is a person's opinions and feelings about his or her own body and physical appearance. ____You appreciate your body for its capabilities and accept its imperfections.

    ____Here are some ideas.

    Recognize your strengths. Different body types are good for different things. What does your body do well? Maybe your speed, strength, or coordination makes you better than others at a certain sport. That may be basketball, table tennis, mountain biking, dancing, or even running. Or perhaps you have non-sports skills, like drawing, painting, singing, playing a musical instrument, writing, or acting. ____

    Exercise regularly. Exercise can help you look well and feel good about yourself. Good physiques (体形) don't just happen.____ A healthy habit can be as simple as exercising 20 minutes to 1 hour three days a week. Working out can also lift your spirits.

    Respect your body! Practicing good habits regular showering; taking care of your teeth, hair, and skin; wearing clean clothes, and so on can help you build a positive body image.

    ____Your body is just one part of who you are. Your talent for comedy, a quick wit (智慧) and all the other things make you unique. So try not to let small imperfections take over.

A. Use this as an opportunity to discover what you're good at.

B. Be yourself.

C. Having a positive body image means feeling satisfied with the way you look.

D. Just explore talents that you feel good about.

E. They take hard work, regular workouts, and a healthy diet.

F. The good news is that self-image and body image can be changed.

G. So, what can you do to develop a positive body image?