21. Which of the following is the normal cell cycle, primarily regulated at checkpoints?

A. Metaphase in mitosis
B. Anaphase, G1 boundary
C. G1-S boundary
D. S-G2 boundary

22. The phase of mitosis which is associated with the formation of the nuclear envelope is

A. prophase
B. metaphase
C. anaphase
D. telophase

23. At the __________ checkpoint, cell growth is controlled.

A. C
B. G₁
C. G₂
D. S

24. A nuclear envelope forms around each set of sister chromatids in

A. anaphase
B. metaphase
C. prophase
D. telophase

25. In which of the following phase preparations for genome separation are made?

A. C
B. G₁
C. G₂
D. M