Question

Compared to platyhelminthes, which physiological problem was caused the cylindrical body of nematodes? How was that problem solved?

Answer 1

PROBLEM:

Compared to platyhelminthes the cylindrical shape of nematodes cause problem in respiration exclusively via simple diffusion between cells as they contain tissues far from their external environment.

SOLUTION :

The problem was solved if there is presence of an inner cavity in the body filled with fluid which is called as pseudocoelom.

The pseudocoelom will distribute gases and nutrients to the body also helpful in collecting waste. It also serves as a hydrostatic base which maintain the shape of the worm.