The middle layer in body wall of porifera is or The non-cellular layer present between pinacoderm and choanoderm in body wall of poriferans is known as

Options

A. Msoderm
B. Mesenchyme
C. Mesoglea
D. Mesentery

Answer

To answer the question about the middle layer in the body wall of Porifera, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Body Structure of Porifera**: Porifera, commonly known as sponges, have a simple body structure characterized by two main layers: the outer layer called the pinacoderm and the inner layer known as the choanoderm.

2. **Identify the Layers**:
- The **pinacoderm** is the outer layer, which is made up of flat cells called pinacocytes.
- The **choanoderm** is the inner layer, composed of collar cells known as choanocytes that help in water circulation.

3. **Recognize the Middle Layer**: Between the pinacoderm and the choanoderm, there exists a layer that is not cellular. This layer is crucial for the structural integrity and function of the sponge.

4. **Determine the Name of the Middle Layer**: The non-cellular layer found between the pinacoderm and choanoderm is known as **mesenchyme**. This layer is a gelatinous substance that contains various cells and is responsible for the support and transport of nutrients within the sponge.

5. **Select the Correct Option**: Based on the understanding that the middle layer is non-cellular and located between the pinacoderm and choanoderm, the correct answer is **B. Mesenchyme**.

### Final Answer:
The non-cellular layer present between pinacoderm and choanoderm in the body wall of poriferans is known as **mesenchyme**.

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