下列关于细胞生命历程的说法正确的是 A.细胞凋亡发生在胚胎发育

下列关于细胞生命历程的说法正确的是

A.细胞凋亡发生在胚胎发育过程中,细胞分化发生在整个生命过程中

B.多细胞生物个体衰老过程中,既有细胞的衰老死亡,也有大量新细胞经分

裂产生并发生细胞分化,所以个体衰老和细胞衰老无直接关系

C.细胞分化是永久性的变化,一般不可逆转

D.放疗、化疗方法通过抑制癌细胞DNA复制和诱导癌细胞突变成正常细胞,达到治疗的目的

答案

C

相关题目

阅读下面的文言文,完成文后小题。 宣皇帝讳懿,字仲达,
阅读下面的文言文,完成文后小题。 宣皇帝讳懿,字仲达,河内温县孝敬里人,姓司马氏。帝少有奇节,少有奇节,聪明多大略,博学洽闻,伏膺儒教
Mr and Mrs Smith had always spent their summer holidays in New Jersey in the pas
Mr and Mrs Smith had always spent their summer holidays in New Jersey in the past, staying in a small inn(旅店) at the foot of a hill. One year, however, Mr. Smith made a lot of money in his busines
—Are you going to help John with his Chinese this evening? —No,He ________
—Are you going to help John with his Chinese this evening? —No,He ________ to England.He will be back next month. A.returned             B.has returned           C.
When I worked as the general manager of the firm, I sometimes had _____ to visit
When I worked as the general manager of the firm, I sometimes had _____ to visit London on business.   A. opportunity    B. possibility    C. occasion    D. chance
下面表达准确、没有语病的一项是          (    ) A
下面表达准确、没有语病的一项是          (    ) A.温家宝指出,我国首次探月工程的圆满成功,使中华民族千年的奔月梦想开始变为现实,
工业上用氨气(NH3)制取硝酸(HNO3),工业流程为:催化剂
工业上用氨气(NH3)制取硝酸(HNO3),工业流程为:催化剂  催化剂  △  ①4NH3 +5O2=====  4NO +6H2O ②2NO +O2 ===  2NO2        ③3NO2+H2O ===  2HNO3 + NO
右图是某个化学反应的微观模拟示意图。从图中获得的有关
右图是某个化学反应的微观模拟示意图。从图中获得的有关信息不正确的是(O表示一种原子,●表示另一种原子)A.分子由原子构成B.分子间存在一定
设△ABC的内角A,B,C所对的边分别为a,b,c,若bcosC+ccosB=asinA
设△ABC的内角A,B,C所对的边分别为a,b,c,若bcosC+ccosB=asinA,则△ABC的形状为(     ) A.锐角三角形   B.直角三角形   C.钝角三角形   D.不确

最新题目