Pseudoemetamerism occours in

Options

A. Turbellaraia
B. Trematoda
C. Cestoda
D. None of the above

Answer

To solve the question "Pseudoemetamerism occurs in?", we will follow these steps:

### Step 1: Understand Metamerism
- **Definition**: Metamerism refers to the division of the body into repeated segments or metamers, which is a characteristic feature of certain animal groups like annelids (e.g., earthworms) and arthropods (e.g., insects).
- **Key Point**: In true metamerism, each segment contains distinct organs.

**Hint**: Think about how segmentation is a defining trait in certain animal phyla.

### Step 2: Define Pseudoemetamerism
- **Definition**: Pseudoemetamerism is a condition where only the ectoderm appears segmented, without the internal organs being divided into segments.
- **Key Point**: This phenomenon is not true segmentation, as it does not involve the complete body structure.

**Hint**: Focus on the distinction between true segmentation and the appearance of segmentation in pseudoemetamerism.

### Step 3: Identify Organisms with Pseudoemetamerism
- **Relevant Group**: Pseudoemetamerism is found in certain flatworms, specifically in the class Cestoda (tapeworms).
- **Example**: Tapeworms have segments called proglottids, which are superficial segments that can appear as distinct units but do not represent true metamerism.

**Hint**: Recall that proglottids are the segments seen in tapeworms and are key to identifying the correct answer.

### Step 4: Analyze the Options
- **Options Given**:
1. Turbellaria
2. Trematoda
3. Cestoda
4. None of the above
- **Conclusion**: Since pseudoemetamerism is specifically associated with Cestoda (tapeworms), this is the correct answer.

**Hint**: Eliminate options by recalling the characteristics of each class mentioned.

### Final Answer
The correct answer is **Cestoda** (option 3).