Question

The Excretory organ of cockroach and other insects are
A) Nephridia
B) Gizzard
C) Flame cells
D)Malpighian tubules

Answer 1

Hint: The excretory organ is found in the junction of midgut and hindgut. It consists of branched tubules. It removes waste from the hind gut.

Complete answer:
The excretory system of cockroaches is an osmoregulatory unit. They are composed of highly branched tubules which extend from the alimentary canal. It is a highly convoluted structure. They absorb solutes and water from the hemolymph and remove waste. This system is known as a malpighian tubule system. It is named after Marcello Malpighi.
Nitrogenous waste like urea diffuse from the walls and useful ions like potassium and sodium are transported through active transport. The excreta of cockroach and other insects is mainly composed of urea and uric acid. After reabsorption, the waste moves to the rectum and is released through anus.
Nephridium is an excretory organ present in earthworms.
Flame cells serve as an excretory system in platyhelminthes.
Gizzard is the part of the alimentary canal whose function is to break the food. It is found in insects.

Thus the correct answer is (D). Malpighian tubules are the excretory system of cockroaches.

Additional InformationIn insects which feed on harmful allelochemicals, malpighian tubules rapidly excrete these compounds from the hemolymph.

Note:Excretion of harmful waste and reabsorption of minerals back to hemolymph takes place in malpighian tubules. It helps in excreting excrete nitrogenous waste and other metabolites in the insects and cockroaches.