Which among the following has 23 chromosomes?

Options

A. Spermatogonia
B. Zygote
C. Secondary oocyte
D. Oogonia

Explanation

To determine which among the given options has 23 chromosomes, we can analyze each option step by step:

### Step 1: Understand Chromosome Count
- Humans have a total of 46 chromosomes, organized into 23 pairs.
- Cells can be classified as diploid (2n) or haploid (n). Diploid cells have 46 chromosomes (23 pairs), while haploid cells have 23 chromosomes (1 set).

### Step 2: Analyze Each Option

1. **Spermatogonia**
- Spermatogonia are the precursor cells in the testes that develop into sperm.
- They are diploid (2n), meaning they contain 46 chromosomes (23 pairs).
- **Conclusion**: Spermatogonia do not have 23 chromosomes.

2. **Zygote**
- A zygote is formed by the fusion of two haploid gametes (sperm and egg).
- Each gamete has 23 chromosomes, so when they fuse, the zygote has 46 chromosomes (2n).
- **Conclusion**: The zygote does not have 23 chromosomes.

3. **Secondary Oocyte**
- A secondary oocyte is formed from a primary oocyte through meiosis.
- The primary oocyte is diploid (46 chromosomes), but the secondary oocyte is haploid (23 chromosomes).
- **Conclusion**: The secondary oocyte has 23 chromosomes.

4. **Oogonia**
- Oogonia are the precursor cells in the ovaries that develop into primary oocytes.
- They are diploid (2n) and contain 46 chromosomes (23 pairs).
- **Conclusion**: Oogonia do not have 23 chromosomes.

### Final Conclusion
- The only option that has 23 chromosomes is the **secondary oocyte**.

### Answer: The correct answer is the **secondary oocyte** (Option 3).

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