A：细胞分化，核遗传物质没有发生改变，但mRNA有变化
B：细胞凋亡，相关基因活动加强，有利于个体的生长发育
C：细胞衰老，代谢速率减慢，细胞内各种酶活性降低，细胞膜通透性改变
D：细胞癌变，细胞膜的成分发生改变，有的产生甲胎蛋白、癌胚抗原等物质
选择合适的字音填在横线上。
hé huó
温和____ 和面____ 我和你____ 和平____
jué jiào
睡觉____ 发觉____ 觉得____ 午觉____
OH﹣
NO3﹣
Cl﹣
CO32﹣
SO42﹣
H+
﹣﹣
溶、挥
溶
Na+
Ca2+
微
不
Ba2+
Cu2+
阅读以下两则报道，分析回答：
tidy， everywhere， where， must， find， know， help
I have a good friend，Joanna．I ____her well．She is a nice girl but she is not very ____．You can see books, pens and notebooks are ____ in her room．In the school, she always asks．" ____is my pen? Where are my books? And where are ．．．?" I often ____her．This morning, Joanna can't ____her English notebook， and she ____find it．so she asks me to help her．
