The answer is the first one (A): the $G_{1}$ phase.
Explanation for each option:
A) $G_{1}$ phase: The $G_{1}$ phase is known to have the biggest extremes in duration. This phase can vary significantly depending on the cell type and external conditions. Some cells may spend a very short time in $G_{1}$, while others may remain in this phase for an extended period before progressing to the next phase.
B) V phase: There is no recognized "V phase" in the standard cell cycle. This option is incorrect.
C) S phase: The S phase, where DNA replication occurs, has a more consistent duration across different cell types. While there can be some variation, it is not as extreme as in the $G_{1}$ phase.
D) $G_{0}$ phase: The $G_{0}$ phase is a resting state where cells exit the cell cycle and do not actively prepare for division. While cells can remain in $G_{0}$ for varying lengths of time, it is not considered part of the active cell cycle phases and thus not directly comparable in terms of duration extremes.
E) $G_{2}$ phase: The $G_{2}$ phase, which follows DNA replication and precedes mitosis, also has a relatively consistent duration compared to the $G_{1}$ phase.
Summary:
The $G_{1}$ phase has the biggest extremes in duration among the phases of the cell cycle.
Answered
