生物体的所有细胞中染色体都是成对存在的．
读“地壳结构示意图”，完成第问题。
福寿螺是一种危害极大的外来物种．如图是防治福寿螺的稻鸭生态农业模式．请回答：
A. You're welcome.
B. What shape would you like?
C. I'd like some cherries, too.
D. What kind of pudding would you like?
E. Yes. I want to buy a pudding.
A: Can I help you?
B:____
A:____
B: I'd like a chocolate pudding.
B: I'd like a heart-shaped pudding.
A: Anything else?
B:____How much are they?
A: 70 yuan.
B: Here is the money.
A: Thank you.
