Directions : In the following questions a statement of Assertion (A) ...
Flame cells are the excretory organs of Platyhelminthes and other related animals which possess flickering cilia or flagella for driving the excretory products.
Directions : In the following questions a statement of Assertion (A) ...
• Assertion: Excretory organs are absent in phylum Platyhelminthes.
• Reason: Flame cells are the excretory organs of Platyhelminthes.
The correct answer is option D, i.e., "Assertion (A) is false but reason (R) is true."
Explanation:
• Platyhelminthes is a phylum of flatworms that are bilaterally symmetrical and acoelomate.
• These organisms possess a primitive excretory system that is composed of flame cells, also known as protonephridia.
• Flame cells are specialized cells that are responsible for osmoregulation and excretion of metabolic wastes.
• These cells possess cilia that beat in coordination to create a water current, which helps in the elimination of waste materials from the body.
• However, flame cells are not considered true excretory organs since they do not have a duct system to transport the waste products outside the body.
• Therefore, the assertion that excretory organs are absent in phylum Platyhelminthes is false, but the reason that flame cells are the excretory organs of Platyhelminthes is true.