at the cycle in the diagram in question \( \mathbf{6} \). the first stage that will not happen if the egg cell is fertilised.

Based on your description, it appears you're referring to the stages of the **cell cycle** in the context of fertilization. When an egg cell (oocyte) is fertilized, it undergoes specific changes to transition into a zygote, initiating embryonic development. Here's a breakdown of what happens: 1. **Oocyte Arrest:** - **Primary Oocytes** are arrested in the **prophase I** stage of **meiosis** until fertilization occurs. 2. **Completion of Meiosis I:** - Upon hormonal signals leading up to ovulation, the primary oocyte completes meiosis I, resulting in a **secondary oocyte** and the first polar body. 3. **Arrest in Metaphase II:** - The secondary oocyte is then arrested again, this time in **metaphase II** of meiosis, and awaits fertilization. 4. **Completion of Meiosis II:** - **Fertilization** triggers the completion of meiosis II, producing the **ovum (mature egg)** and a second polar body. The fusion of the sperm and egg nuclei forms the **zygote**, marking the beginning of the **interphase** of the zygote's cell cycle. Given this process, the first **interphase** phase that typically occurs in the standard cell cycle—**G1 phase**—**does not occur** in the zygote immediately after fertilization. Instead, the zygote transitions directly into the **S phase** (DNA synthesis) following the completion of meiosis II. ### **Conclusion** **The first stage that does not occur if the egg cell is fertilized is the G₁ phase of interphase.**