Question

The excretory organs of Mollusca are

• A. Metanephridia
• B. Nephridia
• C. Green glands
• D. Protonephridia

Answer 1

The correct option is A Metanephridia

There are different types of excretory organs in different organisms. A metanephridium is a type of excretory gland. This gland is found in annelids, arthropods and molluscs. A metanephridium consists of an opening into the body cavity. This opening is funnel shaped and contains cilia. This is connected to a duct which opens to the exterior. These ciliated tubules pumps the water which is carrying the wastes out of the organism by directing them to nephrostomes. This waste is passed out of the organism at the nephridiopore. The primary urine produced by filtration of blood is modified into secondary urine through selective reabsorption by the cells lining the metanephridium.

Thus, the correct answer is option A.