What is present in mesoglea of ctenophores which make it a loose layer of cells?

Options

A. Amoebocytes
B. Elastic cells
C. Nerve cells and muscle cells
D. All the above.

Answer

**Step-by-Step Solution:**

1. **Understanding Mesoglea**: Mesoglea is a gelatinous substance found in ctenophores (and cnidarians) that serves as a supportive layer between the outer epidermis and the inner gastrodermis.

2. **Components of Mesoglea**: The mesoglea is not just a simple jelly-like substance; it contains various types of cells and fibers that contribute to its structure and function.

3. **Identifying the Cells**:
- **Amoebocytes**: These are mobile cells that can perform functions such as phagocytosis, helping in the immune response and nutrient transport.
- **Elastic Cells**: These cells provide elasticity to the mesoglea, allowing it to maintain its shape and support the organism's structure.
- **Nerve Cells**: Nerve cells in the mesoglea are involved in transmitting signals and coordinating movements.
- **Muscle Cells**: Muscle fibers present in the mesoglea contribute to the movement and contraction of the ctenophore.

4. **Conclusion**: Since mesoglea contains all of the above-mentioned cell types (amoebocytes, elastic cells, nerve cells, and muscle cells), it can be concluded that the mesoglea is a complex structure made up of various components that contribute to its loose and jelly-like nature.

5. **Final Answer**: Therefore, the correct answer is that all of these (amoebocytes, elastic cells, nerve cells, and muscle cells) are present in the mesoglea of ctenophores.

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