A change in the amount of yolk and its distribution in the egg will affect :-

Options

A. number of blastomeres produced
B. fertilization
C. Formation of zygote
D. pattern of cleavage

Answer

### Step-by-Step Solution:

1. **Understanding Yolk in Eggs**:
- Yolk is a nutrient-rich substance in the egg that provides nourishment to the developing embryo. The amount and distribution of yolk can influence various developmental processes.

2. **Identifying the Impact of Yolk Amount and Distribution**:
- A change in the amount of yolk and its distribution will primarily affect the cleavage patterns during early embryonic development.

3. **Types of Cleavage**:
- There are two main types of cleavage patterns: **holoblastic** and **meroblastic**.
- **Holoblastic Cleavage**: Occurs in eggs with little to no yolk. The cleavage furrows divide the entire egg into smaller cells (blastomeres).
- **Meroblastic Cleavage**: Occurs in eggs with a significant amount of yolk. The cleavage furrows do not divide the entire egg; instead, they only divide the portion of the egg that is not occupied by yolk.

4. **Effect on Blastomeres**:
- The number of blastomeres produced is influenced by the cleavage pattern. In holoblastic cleavage, more blastomeres can be formed as the entire egg divides. In meroblastic cleavage, fewer blastomeres are formed since only a part of the egg divides.

5. **Conclusion**:
- Therefore, a change in the amount of yolk and its distribution will affect the pattern of cleavage and consequently the number of blastomeres produced. It may also impact fertilization and the formation of the zygote indirectly, but the most direct effect is on the cleavage pattern.

### Final Answer:
A change in the amount of yolk and its distribution in the egg will affect the pattern of cleavage and the number of blastomeres produced.

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