When do the egg cells of a human female begin meiosis ?

Options

A. Before she is born
B. During ovulation
C. At the start of puberty
D. During menstruation

Answer

**Step-by-Step Solution:**

1. **Understanding Meiosis**: Meiosis is a type of cell division that reduces the chromosome number by half, leading to the formation of gametes (egg and sperm cells).

2. **Oogenesis**: The process of egg cell formation in females is known as oogenesis. This process is crucial for the development of egg cells (ova).

3. **Timing of Meiosis in Females**: In human females, the formation of egg cells begins during embryonic development. Specifically, this occurs while the female fetus is still developing in the womb.

4. **Formation of Oogonia**: During fetal development, millions of gamete mother cells, known as oogonia, are formed in the ovaries.

5. **Initiation of Meiosis**: These oogonia begin the process of meiosis during the fetal stage. However, they do not complete meiosis at this time.

6. **Arrest at Prophase I**: The oogonia undergo meiosis but get arrested at the prophase I stage. At this point, they are referred to as primary oocytes.

7. **Resumption of Meiosis**: After birth, these primary oocytes remain in this arrested state until puberty. At puberty, the primary oocytes resume meiosis, leading to the formation of secondary oocytes and eventually the ovum.

8. **Conclusion**: Therefore, the egg cells of a human female begin meiosis during embryonic development, specifically before birth.

**Final Answer**: The egg cells of a human female begin meiosis during embryonic development, before she is born.

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