Flame cells are excretory organs of A) HydraB) HydrillaC) CockroachD) Planaria

The correct answer is D) Planaria.
1. What are Flame Cells?
o Flame cells are specialized excretory structures found in flatworms, such as planaria. They are part of the protonephridial system, which is a network of tubules that helps in osmoregulation and excretion.
o The name "flame cell" comes from the flickering movement of cilia inside the cell, which resembles the flickering of a flame.
2. Function of Flame Cells:
o Flame cells function in the removal of metabolic waste and excess water from the body.
o Cilia within the flame cell create currents that draw waste fluids into the tubules. These wastes are then excreted out of the body through excretory pores.
3. Planaria and Flame Cells:
o Planaria, which belong to the phylum Platyhelminthes, are freshwater flatworms with simple body structures. They rely on flame cells for excretion and osmoregulation due to the lack of more advanced excretory organs like kidneys.
4. Why Not the Other Options?
o A) Hydra:
 Hydra belongs to the phylum Cnidaria and does not have flame cells. Excretion in hydra occurs through diffusion across the body surface.
o B) Hydrilla:
 Hydrilla is an aquatic plant and does not have specialized excretory structures like flame cells. Plants excrete waste through structures like stomata or lenticels.
o C) Cockroach:
 Cockroaches belong to the phylum Arthropoda and have Malpighian tubules as their excretory organs, not flame cells.
Flame cells are the excretory organs of planaria, making D) Planaria the correct answer.