Mesoderm is present as scattered pouches in between the ectoderm and endoderm in

Options

A. Annelids
B. Echinoderms
C. Molluscs
D. Aschelminthes

Explanation

To answer the question "Mesoderm is present as scattered pouches in between the ectoderm and endoderm in", we can follow these steps:

### Step 1: Understand the Germ Layers
- The three primary germ layers in animals are ectoderm, mesoderm, and endoderm. The ectoderm is the outer layer, the endoderm is the inner layer, and the mesoderm is the middle layer.

**Hint:** Remember the arrangement of germ layers in animals: ectoderm (outer), mesoderm (middle), endoderm (inner).

### Step 2: Define Coelom
- A coelom is a body cavity that is completely lined by mesoderm. There are three types of body cavity arrangements:
1. Acoelomate (no body cavity)
2. Pseudocoelomate (body cavity not completely lined by mesoderm)
3. Coelomate (body cavity completely lined by mesoderm)

**Hint:** Coelom refers to the body cavity; think of how it is classified based on mesodermal lining.

### Step 3: Identify Pseudocoelomate
- In pseudocoelomates, the body cavity is present but is not completely lined with mesoderm. Instead, it has mesodermal pouches scattered within the cavity.

**Hint:** Focus on the term "scattered pouches" which indicates that the mesoderm is not continuous but rather in small sections.

### Step 4: Relate to Phyla
- The question specifies that mesoderm is present as scattered pouches. This characteristic is typical of the phylum Aschelminthes (also known as Nematoda), where the body cavity is a pseudocoelom.

**Hint:** Recall that Aschelminthes is known for having a pseudocoelom, which fits the description of scattered mesodermal pouches.

### Step 5: Conclusion
- Based on the understanding that the mesoderm is present as scattered pouches in between the ectoderm and endoderm, the answer to the question is **Aschelminthes**.

**Final Answer:** Aschelminthes

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