Middle layer in the body wall of cnidarians is

Options

A. ectoderm
B. mesoglea
C. endoderm
D. mesoderm

Answer

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

### Step-by-Step Solution:

1. **Identify the Tissue Layers in Cnidarians**: Cnidarians, such as jellyfish, corals, and sea anemones, have a simple body structure characterized by two main tissue layers: the outer layer and the inner layer.

2. **Define the Outer Layer**: The outer layer of the body wall in cnidarians is called the **epidermis**. This layer is responsible for protection and sensory functions.

3. **Define the Inner Layer**: The inner layer is known as the **gastrodermis**. This layer lines the digestive cavity and is involved in digestion and nutrient absorption.

4. **Identify the Middle Layer**: Between the epidermis and the gastrodermis, there is a non-living jelly-like substance called **mesoglea**. This layer is not a tissue layer but serves as a supportive structure, providing buoyancy and structure to the organism.

5. **Conclusion**: Therefore, the middle layer in the body wall of cnidarians is called **mesoglea**.

### Final Answer:
The middle layer in the body wall of cnidarians is **mesoglea**.

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