Question

Flame cells are excretory organs of
A) Hydra
B) Hydrilla
C) Cockroach
D) Planaria

Answer 1

Hint: Flame cells are excretory cells found in freshwater invertebrates. These cells are collectively called protonephridia.

Complete Answer:
Flame cells are specialized in function and are dedicated to excretion. In simple animals like flatworms, these cells function like kidneys and remove nitrogenous waste material from the body.
These cells are found in freshwater invertebrates including flatworms and rotifers. Flame cells have a nucleus with a cup-like projecting structure. These cells are flagellated and which covers the inner surface of the cup.
The flagella have a beating movement that looks like a flame and this is the reason for the name. The cup-like structure is a tube which has cilia on its inner surface. These cilia help to move liquid matter through it.
The tube cell has an external opening called nephrology. The function of these cells is similar to kidneys, excretion, and osmoregulation by the maintenance of ionic balance in the body.

So, the correct answer is 'Planaria'

Note: Cockroaches have an elaborate excretory system. This consists of malpighian tubules that function similarly to the kidney. Each malpighian tubule has glandular and ciliated cells lining the inner side of the tubule. These cells efficiently absorb nitrogenous waste. The nitrogenous waste is converted into uric acid since cockroaches are uricotelic which is later excreted through the hind gut.