The path of water in a sponge is

Options

A. Dermal ostia `to` Gastral ostia ` to ` Osculum
B. Dermal ostia ` to ` Gastral ostia `to ` spongocoel ` to` Osculum
C. Osculum ` to ` Spongocoel ` to ` Choanocytes ` to ` Ostia
D. Pinacocytes `to ` Choanocytes `to` Enteron ` to ` Osculum

Answer

**Step-by-Step Solution:**

1. **Understanding the Structure of Sponges**:
- Sponges belong to the phylum Porifera. They have a unique body structure characterized by numerous pores.

2. **Water Entry**:
- Water enters the sponge through tiny openings called **dermal ostia**. These are small pores located on the surface of the sponge.

3. **Movement to the Central Cavity**:
- After entering through the dermal ostia, water flows into the **gastral cavity** (also known as the spongocoel). This is the central cavity of the sponge.

4. **Role of Choanocytes**:
- The spongocoel is lined with specialized cells called **choanocytes**. These cells have flagella that beat to create a current, helping to push the water through the sponge.

5. **Exiting the Sponge**:
- Finally, the water exits the sponge through a large opening called the **osculum**. This is the excretory structure of the sponge where the water leaves after passing through the sponge.

6. **Flow Path Summary**:
- The complete path of water in a sponge can be summarized as:
- Dermal ostia → Gastric cavity (spongocoel) → Osculum

7. **Final Answer**:
- Therefore, the correct flow of water in a sponge is **dermal ostia → gastric cavity → spongocoel → osculum**. The answer is option B.

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