A:切断a处的酶为限制性核酸内切酶
B:连接a处的酶为DNA连接酶
C:切断b处的酶为解旋酶
D:切断b处的为限制性内切酶
和1相邻的两个数是____和____.
根据问句,选择合适的答句。
①Does Jane have a soccer ball?____ A. OK.
②Do you have a baseball bat?____ B. It's in my bedroom.
③Let's go!____ C. Yes, she does.
④Where's your baseball?____ D. No, I don't.
⑤Is it under the teacher's desk?____ E. Yes, it is.