题干

生物学基础研究成果已应用到医药、农药等领域.下列叙述中,符合这种情况的是(  )

①根据DNA分子的特异性,进行亲子鉴定;

②基于细胞呼吸的原理,采用套种、合理密植、大棚种植等措施增加作物产量;

③在细胞膜的功能研究基础上,开发人工“肾”治疗尿毒症;

④根据染色体变异原理,培育出三倍体无子西瓜.

A:①②③

B:①②④

C:①③④

D:②③④

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答案(点此获取答案解析)

C

同类题5

根据首字母提示,拼写单词。

    Sam and Tom were identical(同样的) twins. They were so identical that even their mother found it d____to tell one from the other. But except for their looks, everything else about them was different.

    Tom had no friends, w____Sam was a great friendship maker. Sam loved sweets, but Tom loved spicy food and h____sweets. Sam was generous and selfless, Tom was greedy and selfish!

    As Sam and Tom grew up, their father wanted to s____his fortune equally. However, Tom did not agree, and he argued that whoever proved to be smarter and stronger would have to get a b____share of the wealth.

    Sam agreed. Their father decided to organize a competition b____the two. He asked the two sons to walk as long as they could, and return home before sunset.

    The following day, Sam and Tom set out to walk. It was a rather sunny day. Sam walked slowly and steadily, while Tom ran q____as he aimed at winning the race and gained a greater portion of his father's wealth.

    Sam knew that it would be ideal to walk as far as possible till noon, and start for home at noon, as it would take the same amount of time to walk back home. K____this, Sam decided to turn back for home at noon so as to reach home on time.

    However, Tom, with his greed to earn more w____ didn't try to return home even after mid-noon. He walked twice as long as Sam, and thought he would still be able to return home before sunset. U____ he lost the race at last only because of his greed.