The mesolamella/mesogloea is formed by

Options

A. Epidermis
B. Gastrodermis
C. Epidermis and gastrodermis
D. Mesoderm.

Answer

**Step-by-Step Solution:**

1. **Understanding Mesogloea/Mesolamella**: The mesogloea (or mesolamella) is a gelatinous substance found between the two epithelial layers (ectoderm and endoderm) in coelenterates (Cnidaria).

2. **Identifying the Layers**: In organisms like Hydra, the outer layer is called the ectoderm, which forms the epidermis, while the inner layer is the endoderm, which forms the gastrodermis.

3. **Absence of Mesoderm**: Unlike higher organisms that have a mesoderm as the middle layer, coelenterates do not possess a mesoderm. Instead, they have mesogloea as the middle layer.

4. **Formation of Mesogloea**: The mesogloea is formed by the combination of the ectoderm and endoderm. It is situated between these two layers, providing structural support and elasticity.

5. **Functions of Mesogloea**: The mesogloea acts as an internal skeleton and provides elasticity to the organism, aiding in its movement and shape maintenance.

6. **Conclusion**: Therefore, the mesogloea is formed by the ectoderm and endoderm layers of the organism.

**Final Answer**: The mesogloea is formed by the ectoderm and endoderm.

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