How many structures in the list given below are haploid?
Spermatid, secondary oocyte, primary spermatocyte, ovum, sperm, oogonia, spermatogonia, polar body

Options

A. Six
B. Four
C. Two
D. Five

Answer

To determine how many structures from the given list are haploid, we will analyze each structure one by one:

1. **Spermatid**:
- Spermatids are formed from secondary spermatocytes through meiosis. Since they are produced by meiosis, they are haploid.
- **Haploid Status**: Yes (N)

2. **Secondary Oocyte**:
- Secondary oocytes are formed from primary oocytes through meiosis. Therefore, they are also haploid.
- **Haploid Status**: Yes (N)

3. **Primary Spermatocyte**:
- Primary spermatocytes are derived from spermatogonia through mitosis. They are diploid.
- **Haploid Status**: No (2N)

4. **Ovum**:
- The ovum is the female gamete and is formed by meiosis. Thus, it is haploid.
- **Haploid Status**: Yes (N)

5. **Sperm**:
- Sperm is the male gamete and is also formed by meiosis. Hence, it is haploid.
- **Haploid Status**: Yes (N)

6. **Oogonia**:
- Oogonia are the primordial germ cells in females and are diploid, formed by mitosis.
- **Haploid Status**: No (2N)

7. **Spermatogonia**:
- Spermatogonia are the primordial germ cells in males and are also diploid, formed by mitosis.
- **Haploid Status**: No (2N)

8. **Polar Body**:
- Polar bodies are formed during the meiosis of oocytes and are haploid.
- **Haploid Status**: Yes (N)

Now, let's summarize the haploid structures identified:

- **Haploid Structures**:
- Spermatid (Yes)
- Secondary Oocyte (Yes)
- Ovum (Yes)
- Sperm (Yes)
- Polar Body (Yes)

**Total Haploid Structures**: 5

Thus, the answer to the question is that there are **5 haploid structures** in the list.