In mesolecithal eggs , the cleavage is :

Options

A. Equal , holoblastic
B. Unequal holoblastic
C. Meroblastic
D. Discoidal

Answer

To solve the question regarding the type of cleavage in mesolecithal eggs, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Mesolecithal Eggs**:
- Mesolecithal eggs contain a moderate amount of yolk. This yolk is not distributed evenly throughout the egg but is concentrated more in one hemisphere than the other.

2. **Defining Cleavage**:
- Cleavage refers to the series of cell divisions that occur after fertilization. The nature of cleavage can vary based on the amount and distribution of yolk in the egg.

3. **Types of Cleavage**:
- There are two main types of cleavage:
- **Holoblastic Cleavage**: This type of cleavage occurs when the entire egg is divided into smaller cells. It can be either equal or unequal.
- **Meroblastic Cleavage**: This occurs when only a part of the egg divides, typically seen in eggs with a large amount of yolk.

4. **Analyzing Mesolecithal Cleavage**:
- In mesolecithal eggs, the cleavage is holoblastic because the entire egg divides, but it is also unequal due to the uneven distribution of yolk. This means that the cleavage furrows do not divide the egg into equal-sized blastomeres.

5. **Conclusion**:
- Therefore, the cleavage in mesolecithal eggs is characterized as **unequal holoblastic cleavage**.

### Final Answer:
The cleavage in mesolecithal eggs is **unequal holoblastic** (Option B).

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