In the most simple type of canal system of Porifera, which of the following ways exhibit water flow?

Options

A. Ostia `rarr` Spongocoel `rarr` Osculum `rarr` Exterior
B. Spongocoel `rarr` Ostia `rarr` Osculum `rarr` Exterior
C. Osculum `rarr` Spongocoel `rarr` Ostia `rarr` Exterior
D. Osculum `rarr` Ostia `rarr` Spongocoel `rarr` Exterior

Explanation

**Step-by-Step Solution:**

1. **Understanding the Structure of Porifera**: Porifera, commonly known as sponges, have a porous body structure. This means they contain numerous small openings or pores.

2. **Identifying Types of Pores**: There are two main types of pores in sponges:
- **Inhalant Pores (Ostea)**: These are the pores through which water enters the sponge.
- **Exhalant Pores (Osculum)**: These are the larger openings through which water exits the sponge.

3. **Central Cavity**: Inside the sponge, there is a central cavity known as the **Spongeocoel**. This cavity plays a crucial role in the water flow system.

4. **Canal System**: The canal system in sponges facilitates the movement of water. Water flows through this system, allowing the sponge to filter nutrients and oxygen from the water.

5. **Water Flow Pathway**:
- Water enters through the **inhalant pores (ostea)**.
- It then flows into the **central cavity (spongeocoel)**.
- Finally, it exits through the **exhalant pores (osculum)** into the external environment.

6. **Importance of Water Flow**: The flow of water is essential for sponges as it helps in bringing food and oxygen into their bodies while removing waste products like carbon dioxide and nitrogenous waste.

7. **Conclusion**: The correct pathway for water flow in the simplest type of canal system of Porifera is from ostea to spongeocoel to osculum and then to the exterior.

**Final Answer**: The water flow in the simplest type of canal system of Porifera is from **Ostea → Spongeocoel → Osculum → Exterior**.

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