题干

某生物小组做了“探究玉米种子萌发的环境条件”实验:在甲、乙两个烧杯中分别放等量的棉花,再将相同数量的玉米种子放在上面,进行如表的培养,数日后记录发芽情况如表.通过实验可以看出,下列哪个选项是本实验验证的影响种子萌发所必须的外界条件(    )

装置

种子所处的环境

实验结果

甲

干燥的棉花,置于25℃的橱柜中

种子不萌发

乙

潮湿的棉花,置于25℃的橱柜中

种子萌发

A:适量的水分

B:适宜的温度

C:充足的空气

D:棉花

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答案(点此获取答案解析)

A

同类题5

阅读下面的短文并用英语回答问题,并将答案写在答题卷上标有题号的横线上。

(an extract from Stuart Little)

    When Mrs. Frederick C. Little's second son arrived, everybody noticed that he was not much bigger than a mouse. The truth of the matter was, the baby looked very much like a mouse in every way. He was only about two inches high; and he had a mouse's sharp nose, a mouse's tail, a mouse's whiskers(胡须),and the pleasant, shy manner of a mouse. Before he was many days old he was not only looking like a mouse but acting like one, too-wearing a gray hat and carrying a small cane(手杖).Mr. and Mrs. Little named him Stuart, and Mr. Little made him a tiny bed.

    Unlike most babies, Stuart could walk as soon as he was born. Mrs. Little saw right that the baby clothes she had provided were unsuitable, and she set to work and made him a fine little blue suit. Every morning, before Stuart dressed. Mrs. Little went into his room and weighed him on a small scale(称)which was really used for weighing letters. At birth Stuart could have been sent by first class mail, but his parents preferred to keep him rather than send him away. At the age of a month, he had gained only a third of an ounce(盎司), his mother was so worried that she sent for the doctor.

    The doctor was happy with Stuart and said that it was very unusual for an American family to have a mouse. He took Stuart's temperature and found that it was 98.6, which is normal for a mouse. Everything seemed to be all right, and Mrs. Little was pleased to get such a good report.

    "Feed him up!" said the doctor cheerfully, as he left.

    The home of the Little family was a pleasant place near a park in New York City. In the mornings, the Littles were up early as a general rule. Stuart was a great help to his parents, and to his old brother, because of his small size and because he could do things that a mouse can do and was willing to do them.