Question

The excretory organ of flatworms (Platyhelminthes) is
A)Flame cells
B)Nephridia
C)Malpighian tubules
D)Renette glands

Answer 1

Hint: Flatworms belong to the phylum of invertebrates. They are simple animals that have soft bodies. Platyhelminthes is the largest phylum of animals which do not have body cavities. They do not have a definite anus, circulatory, skeletal or respiratory system.

Complete answer:
To solve this question, we must know about the excretory organ of flatworms. Flatworms do not have internal body cavities. The flattened shape of the body helps in diffusion of nutrients and oxygen. The digestive system has only one opening which is meant for intake of nutrients and removal of undigested waste. So the food cannot be processed continuously.

The flatworms have specialised cells which have cilia like structure which beats continuously to remove the nitrogenous wastes. These cells are called the flame cells.
Nephridia- It is the excretory organ present in earthworms (annelids). It functions like a kidney.
Malpighan tubules- It is the excretory and osmoregulatory organ of cockroach (insects).
Rennate glands- It is a secretory-excretory organ present in the nematodes.

Hence, the correct answer is option (A)

Note: Platyhelminthes are the simplest animals having a dedicated excretory system. The flame cells function as a kidney for removing waste materials. The bundles of flame cells are called protonephridia. The flame cells regulate the osmotic pressure and help in maintaining the ionic balance of the organism. The villi present in the flame cells also helps in reabsorption of ions.