In chordates primary egg membranes are formed when :–

Options

A. The egg remain with in ovary
B. The egg discharged from ovary
C. The egg passes through oviduct
D. The egg passes out of oviduct

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks when the primary egg membranes are formed in chordates. It is essential to know what primary egg membranes are and their significance.

2. **Identifying Primary Egg Membranes**: In chordates, the primary egg membrane is known as the zona pellucida. This membrane serves as an outer protective layer for the ovum (egg).

3. **Formation of the Zona Pellucida**: The primary egg membrane (zona pellucida) is formed while the egg is still within the ovary. This is the crucial point as it indicates the timing of the membrane's formation.

4. **Role of the Zona Pellucida**: The zona pellucida not only protects the egg but also provides nutritional support. It is formed before the egg is discharged from the ovary.

5. **Process of Egg Discharge**: Once the egg is discharged from the ovary, it is no longer in the protective environment of the ovary. At this stage, the egg is vulnerable and does not have the primary membrane formed yet.

6. **Conclusion**: Therefore, the correct answer to the question is that the primary egg membranes are formed when the egg is still within the ovary.

**Final Answer**: In chordates, primary egg membranes are formed when the egg remains within the ovary.

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