A：从细胞水平分析，细胞分化时细胞形态、结构和功能发生了改变
B：从细胞器水平分析，细胞分化是细胞器的种类、数目改变的结果
C：从核酸角度分析，细胞分化是基因选择性表达的结果
D：从蛋白质角度分析，细胞分化是蛋白质种类、数量改变的结果，这是细胞分化根本原因
下列有关输血与血型的叙述错误的是（ ）
直线l经过点P（1，﹣1），且它的倾斜角是直线x﹣y+2=0的倾斜角的2倍，那么直线l的方程是____
阅读短文，选择正确的答案。
Chen Jie and Chen Lin are sisters. Chen Jie is 14. She's 2 years younger than Chen Lin. But she's taller than Chen Lin. Chen Jie is 46 kilograms. She's l kilogram heavier than Chen Lin. Chen Jie likes sports. She plays sports every day. So she's stronger than Chen Lin. Chen Jie has short hair, but Chen Lin has long hair. They often wear the same size shoes. They wear size 36. They love each other.
