Mosaic cleavage occurs in

Options

A. Camel
B. Dog Fish
C. Whale
D. Echinococcus.

Answer

### Step-by-Step Solution:

1. **Understanding Mosaic Cleavage**:
- Mosaic cleavage, also known as determinate cleavage, is a type of embryonic development where the fate of each cell is predetermined. This means that each cell in the early embryo has a specific role and cannot develop into a complete organism on its own.

**Hint**: Remember that in mosaic cleavage, the fate of the cells is predetermined.

2. **Identifying Characteristics**:
- In mosaic cleavage, the cells divide in a way that they form a mosaic pattern. This is different from indeterminate cleavage, where cells can develop into any type of cell and can potentially form a complete organism.

**Hint**: Think about how the cells are organized and their potential to develop into complete organisms.

3. **Recognizing Organisms**:
- The question provides four options: camel, chicken, dogfish, whale, and echinococcus. We need to identify which of these organisms undergoes mosaic cleavage.

**Hint**: Consider the classification of these animals as either protostomes or deuterostomes.

4. **Classifying the Options**:
- Camel, chicken, dogfish, and whale are all classified as deuterostomes. In contrast, echinococcus is classified as a protostome.

**Hint**: Recall that mosaic cleavage is typically found in protostomes.

5. **Conclusion**:
- Since echinococcus is the only organism listed that belongs to the protostomes, it is the correct answer for where mosaic cleavage occurs.

**Final Answer**: Mosaic cleavage occurs in **echinococcus**.