题干

下列关于遗传学的基本概念的叙述中正确的是(  )

A:后代同时出现显性性状和隐性性状的现象就叫性状分离

B:纯合子杂交产生的子一代所表现的性状就是显性性状

C:不同环境下,基因型相同,表现型不一定相同

D:兔的白毛和黑毛,狗的长毛和卷毛都是相对性状

上一题 下一题 0.0难度 选择题 更新时间:2017-07-14 05:56:40

答案(点此获取答案解析)

C

同类题2

阅读理解

    Having experienced a shocking electrical accident, which caused him to become both blind and deaf, James Franco's world became completely dark and quiet for almost ten years. The loss of sight and hearing threw him into such sorrow that he tried a few times to put an end to his life. His family, especially his wife, did their best to tend and comfort him and finally he regained the will to live.

    One hot summer afternoon, he was taking a walk with a stick near his house when a thunderstorm started all at once. He stood under a large tree to avoid getting wet, but he was struck by lightning. Witnesses (目击者) thought he was dead but he woke up 20 minutes later, lying face down in muddy water. He was trembling badly, but when he opened his eyes, he could hardly believe what he saw: a tree and a muddy road. When Mrs. Franco came running up to him, shouting to their neighbors to call for help, he could see her and hear her voice for the first time in nearly ten years.

    The news of James regaining his sight and hearing quickly spread and many doctors came to examine him. Most of them said that he regained his sight and hearing from the shock he got from lightning. However, none of them could give a compelling answer as to why this should happen. The only reasonable explanation given by one doctor was that, since James lost his sight and hearing as a result of a sudden shock, perhaps, the only way for him to regain them was by another sudden shock.