How many structures are haploid ?
Spermatogonia , spermatozoa, spermatids, primary spermatocyte, secondary spermatocyte

Answer

To determine how many structures are haploid among the given options (spermatogonia, spermatozoa, spermatids, primary spermatocyte, secondary spermatocyte), we will analyze each structure step by step.

### Step-by-Step Solution:

1. **Spermatogonia**:
- These are the initial germ cells in the male reproductive system.
- They are diploid, meaning they contain two sets of chromosomes (46 chromosomes, or 23 pairs).
- **Conclusion**: Spermatogonia are not haploid.

2. **Spermatozoa**:
- These are the mature male gametes (sperm cells).
- They are haploid, meaning they contain only one set of chromosomes (23 chromosomes).
- **Conclusion**: Spermatozoa are haploid.

3. **Spermatids**:
- These are the cells that result from the second meiotic division of primary spermatocytes.
- They are also haploid, containing one set of chromosomes (23 chromosomes).
- **Conclusion**: Spermatids are haploid.

4. **Primary Spermatocyte**:
- These are the cells that undergo meiosis to form secondary spermatocytes.
- They are diploid, containing two sets of chromosomes (46 chromosomes).
- **Conclusion**: Primary spermatocytes are not haploid.

5. **Secondary Spermatocyte**:
- These are the cells that result from the first meiotic division of primary spermatocytes.
- They are haploid, containing one set of chromosomes (23 chromosomes).
- **Conclusion**: Secondary spermatocytes are haploid.

### Summary of Findings:
- **Haploid Structures**:
- Spermatozoa
- Spermatids
- Secondary Spermatocytes

- **Total Number of Haploid Structures**: 3

### Final Answer:
There are **3 haploid structures**: spermatozoa, spermatids, and secondary spermatocytes.