题干

“经过突变的基因,对大多数个体是不利的,但却是生物进化的主要因素之一。”这一说法是(    )

A:正确,基因突变虽对多数个体不利,但它为定向的自然选择提供了原材料

B:正确,基因突变对多数个体不利,但突变的方向与生物进化的方向是一致的

C:不正确,因为基因突变会导致个体死亡,不利于生物进化

D:不正确,因为基因突变不利于个体的繁殖,会导致物种的绝灭

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A

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    Taking Care of Your Eyes

    Many of us don't pay much attention to the importance of eye care. It is said that if you take care of your eyes, then you can surely be healthy.____Natural eye care should be put in a number one place.

    There are several causes leading to poor eyesight like not enough food, genes(基因) and aging(老化).____ If you happen to work in front of the computer, it is best to take a break every once in a while.

    Something dirty can cause redness and they will make you feel uncomfortable. It is bad for your eyes, too. If this happens, the best way is to clean your eyes by using cold water.____ For example, sunglasses are not just for fashion but they can also serve as a great way to protect your eyesight from UV rays.

    ____Remember that vitamins A, C and E are good for eyes. Try to eat food groups that have these vitamins. And you should do eye exercises because exercise protects your eyesight, too. If a person exercises regularly and eats the right kind of food, his eyes will stay in good condition for a long time.

    ____ In a word, eye care is very important, no matter how old a person is.

A. Such behavior will do harm to our eyes.

B. What can we do to protect our eyesight?

C. That's why our eyes should be given lots of care.

D. Eating healthy food will do good to your eyesight.

E. You must also try your best to protect your eyes from harmful things.

F. All above are natural ways of eye care that can help us keep healthy eyes.

G. Televisions, computers and reading are also the causes of having poor eyesight.