Questions: In an actively dividing eukaryotic cell, the G1, S, and G2 phases collectively constitute the .

In an actively dividing eukaryotic cell, the $\mathrm{G}_{1}, \mathrm{~S}$, and $\mathrm{G}_{2}$ phases collectively constitute the interphase.

Explanation:

• The cell cycle consists of several phases, including interphase and the mitotic phase (M phase).
• Interphase is the period during which the cell grows and replicates its DNA in preparation for mitosis.
• Interphase is subdivided into three phases: $\mathrm{G}_{1}$ (first gap phase), $\mathrm{~S}$ (synthesis phase), and $\mathrm{G}_{2}$ (second gap phase).
• During $\mathrm{G}_{1}$, the cell grows and performs its normal functions.
• During $\mathrm{~S}$, DNA replication occurs.
• During $\mathrm{G}_{2}$, the cell continues to grow and prepares for mitosis.

Therefore, the correct term to fill in the blank is "interphase."