they have a closed 2-pump system much like our but obviously with only one pump
All insects present an exoskeleton, so all insects are arthropods.
Compound Eyes
Barnacles are crustaceans( a type of arthropods)
fishes do have parallel circulation
polysaccharides
They are invertabrates. Some person on this site said that they are arthropods, but he/she is definetly wrong. They are closely related on the phylum tree, but they aren't exactly arthropods. They are invertabrates. Ps. arthropods are a type of invertabrate. :)
Cardiac Circulation
All insects are arthropods. The phylum Arthropoda contains the classes Insecta (insects), Crustacea (crabs, lobsters, etc), Chelicerata (arachnids) and a few others.
Fish have single-loop circulation.
They express the characteristics inherent to arthropods. All insects are arthropods. Not all arthropods are insects.
Actually, a sea anemone is none of these. Sponges are sessile creatures, arthropods have exoskeletons, and fish swim. Sea anemones are a type of cnidarian. They often reproduce by releasing polyps. They are related to corals and jellyfish.
No. They are not even related to one another. Snails are gastropods, which are a type of mollusk. Insects are arthropods.