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。

修改：在错的词下画一横线，并在该词下面写出修改后的词。

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。

    I used to be very close to my father when I was a child. Whenever I quarrel with my mother, I would turn to my father for comfort. As I got old, the gap between us began to grow, that made it hard for me to start a conversation with him. She had done so much for me but I always took for granted. A week ago, my dad gave me the ride home on his bike. I was so tiring that I fell to asleep against his back. Later my mother told me Dad was happy that we had not been so close for a long time. That day, I hugged Dad thankful with tears in my eyes.

下列有关细胞衰老与个体衰老关系的叙述中，不正确的是（　　）