An example of animals in which mesoderm occurs as scattered pouches between ectoderm and endoderm is

Options

A. (a) Filaria worm
B. (b) Tapeworm
C. (c) Earthworm
D. (d) Lancelet

Answer

To answer the question regarding an example of animals in which mesoderm occurs as scattered pouches between ectoderm and endoderm, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Terms**:
- The question refers to animals with a specific arrangement of tissue layers: ectoderm, mesoderm, and endoderm.
- The term "pseudocoelomate" refers to organisms that have a body cavity (coelom) that is not fully lined with mesoderm. Instead, the mesoderm is present as scattered pouches.

2. **Identifying Animal Groups**:
- Animals can be classified based on their body cavity structure:
- **Acoelomates**: Animals without a body cavity (e.g., flatworms).
- **Pseudocoelomates**: Animals with a body cavity that is not completely lined with mesoderm (e.g., roundworms).
- **Coelomates**: Animals with a body cavity fully lined with mesoderm (e.g., earthworms, mollusks).

3. **Analyzing the Options**:
- The question likely provides multiple-choice options. We need to identify which of these options represents a pseudocoelomate.
- Common examples of pseudocoelomates include nematodes (roundworms) and certain types of worms.

4. **Selecting the Correct Answer**:
- Among the options provided:
- **Filarial Worm**: This belongs to the phylum Nematoda and is a pseudocoelomate.
- **Tape Worm**: This belongs to the phylum Platyhelminthes and is an acoelomate.
- **Earthworm**: This belongs to the phylum Annelida and is a coelomate.
- **Lancelet**: This belongs to the phylum Chordata and is also a coelomate.
- Therefore, the correct example of an animal where mesoderm occurs as scattered pouches is the **Filarial Worm**.

### Final Answer:
The correct answer is **A. Filarial Worm**.

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