In sponges, flow of water current in the spongocoel is maintained by

Options

A. Collar cells
B. Amoeboid cells
C. Epithelial cells
D. All of the above

Answer

**Step-by-Step Solution:**

1. **Understanding the Structure of Sponges**: Sponges are simple aquatic animals that have a porous body structure. They are primarily composed of a gelatinous substance called mesohyl, which is surrounded by two layers of cells.

2. **Identifying the Spongocoel**: The central cavity of the sponge is known as the spongocoel. This is where water flows through, allowing the sponge to filter feed.

3. **Role of Collar Cells**: The flow of water in the spongocoel is maintained by specialized cells called collar cells or choanocytes. These cells line the inner surface of the spongocoel.

4. **Mechanism of Water Flow**: Collar cells have a flagellum (a whip-like structure) that beats to create a current. This movement pulls water into the sponge through small openings called ostia.

5. **Water Movement Direction**: Water enters through the ostia, flows through the spongocoel, and exits through a larger opening called the osculum. The coordinated beating of the flagella of the collar cells facilitates this movement.

6. **Conclusion**: Therefore, the flow of water current in the spongocoel of sponges is maintained by the collar cells.

**Final Answer**: The flow of water current in the spongocoel of sponges is maintained by collar cells (choanocytes).

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