21. Place the following in the order that they occur during transcription initiation:

1 - formation of open complex; 2 - formation of closed complex;

3 - promoter clearance; 4 - synthesis of about 10 nucleotides
(A) 1, 2, 3, 4.
(B) 2, 1, 4, 3.
(C) 2, 1, 3, 4.
(D) 3, 1, 2, 4.
(E) 3, 2, 1, 4.

1. 題目解析這道題目考察的是轉錄啟...