Anaphase promoting complex (APC) is formed by:-

Options

A. Sperm
B. Secondary oocyte
C. Ovum
D. All the above

Answer

To answer the question "Anaphase promoting complex (APC) is formed by:", we will analyze the options provided and determine which one is correct.

### Step-by-Step Solution:

1. **Understanding the Anaphase Promoting Complex (APC)**:
- The Anaphase Promoting Complex (APC) is a crucial protein complex that regulates the cell cycle, particularly the transition from metaphase to anaphase during cell division.
- It is a multi-subunit complex that includes proteins such as ubiquitin, which tags other proteins for degradation.

2. **Analyzing the Options**:
- **Option 1: Sperm**:
- Sperm is a male gamete involved in fertilization but does not play a role in the formation of the APC. Therefore, this option is incorrect.

- **Option 2: Secondary Oocyte**:
- The secondary oocyte is a stage in oogenesis and is involved in the formation of the APC. The APC is formed during oocyte maturation and is responsible for regulating the cell cycle. This option is correct.

- **Option 3: Ovum**:
- The ovum is the mature female gamete. While it is involved in fertilization, it does not directly form the APC. Thus, this option is incorrect.

- **Option 4: All of the above**:
- Since only the secondary oocyte is responsible for the formation of the APC, this option is also incorrect.

3. **Conclusion**:
- Based on the analysis, the correct answer is **Option 2: Secondary Oocyte**.

### Final Answer:
The Anaphase Promoting Complex (APC) is formed by the **Secondary Oocyte**.

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