flame cells are excretory organs of

Options

A. Hydra
B. Hydrilla
C. Cockroach
D. planaria

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about the organism that has flame cells as excretory organs. We need to identify which of the given options (hydra, hydrilla, cockroach, planaria) contains flame cells.

2. **Identifying the Organism**:
- **Hydra**: This is a freshwater organism that does not have specialized excretory organs. Instead, it excretes waste through its general body surface.
- **Hydrilla**: This is an aquatic plant and does not possess flame cells or any excretory organs as animals do.
- **Cockroach**: The excretory system in cockroaches consists of Malpighian tubules, which are different from flame cells.
- **Planaria**: This is a flatworm that belongs to the phylum Platyhelminthes and has flame cells as its excretory organs.

3. **Conclusion**: Since only planaria belongs to the phylum Platyhelminthes and has flame cells as excretory organs, the correct answer is planaria.

4. **Final Answer**: Flame cells are excretory organs of planaria.

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