Question

Which one occurs in molluscs but not in echinoderms?

• A. Flame cells
• B. Malpighian tubules
• C. Kidney
• D. None of the above

Answer 1

The correct option is C Kidney

Echinoderms are a major group of only marine animals. Echinoderms have a simple excretory system and use diffusion to excrete nitrogenous waste in the form of ammonia gas. Whereas excretion in molluscs is carried out by a pair of kidneys (called nephridia) which are the tubular structures that collect fluids from the coelom and exchange salts and other substances with body tissues as the fluid passes along the tubules for excretion.
Thus, the correct answer is option C.