In Which Animal Would Perfusion Be Least Efficient During Gas

Question

In which animal would perfusion be least efficient during gas exchange?
A) a fish
B) a bird
C) a flatworm
D) a human

Accepted Answer

Flatworms rely on diffusion for gas exchange across their body surface, rather than a specialized respiratory system, making perfusion less efficient compared to animals with more complex respiratory systems like fish, birds, and humans.