假定英语课上老师要求同桌之间交换修改作文， 请你修改你同桌写的以下作文。文中共有十处错误，每句中最多有两处。错误涉及一个单词的增加，删除或修改。增加：在缺词处加一个漏字符号（＾），并在其下面写出该加的词。删除：把多余的词用斜线（＼）划掉。注意：1. 每处错误及其修改均仅限一词；

2. 只允许修改10处， 多者（从第11处起）不计分。

Most of the Chinese people think the family with one child is more better than the one with more than one child. For a thing, they want to build a successful career but have few time to bring up more than one child; for other thing, raise only one child they can afford better education for him. But others think this is better to have a big family. They think more children they raise, the better their life will be when they grow old. In my opinions, it's enough for a family to have one child, or population expansion will contribute to a series of problem.

在每种生物的细胞核中，都含有一定数量的形态，大小各部相同的_____，它主要有_____和______组成，在每一条______上一般只有____DNA分子。在DNA上有许多控制生物______的基本单位，每个基本单位就是一个________。