The main difference between protonephridia and metanephridia is that
A) protonephridia are involved in osmoregulation, whereas metanephridia are involved in excretion.
B) protonephridia consist of blind flame cells, whereas metanephridia consist of tubules open at both ends.
C) protonephridia are involved in excretion, whereas metanephridia are involved in osmoregulation.
D) protonephridia consist of tubules open at both ends, whereas metanephridia consist of blind flame cells.
E) protonephridia are found in annelids and metanephridia are found in flatworms.

Question

Quizplus · Accepted Answer

Protonephridia consist of a network of tubules ending in flame cells that are not open to the exterior, functioning in osmoregulation and excretion by filtering body fluids. Metanephridia, on the other hand, consist of tubules that are open at both ends, allowing the direct passage of wastes from the body fluid into the tubule and then out of the body, serving both osmoregulation and excretion functions.

The Main Difference Between Protonephridia and Metanephridia Is That