Answer:
The cnidarian has a much simpler neural system system (neural net of nerve cells), with it's only goal to find food and survive, compared to the more brain-like (ganglia and brain) structure of the mollusk who needs to be able to hide from predators and prey as well as get away as quick as possible to ensure to survival.
Explanation:
I don't know if it's 100% right but its the best I could do. Hope it helps!
