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.
Yes, arthropods do have internal body tissue. However, they do not have bones. Animals without bones are called invertebrates.
Barnacles are crustaceans( a type of arthropods)
Compound Eyes
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. :)
All insects are arthropods. The phylum Arthropoda contains the classes Insecta (insects), Crustacea (crabs, lobsters, etc), Chelicerata (arachnids) and a few others.
Cardiac Circulation
They express the characteristics inherent to arthropods. All insects are arthropods. Not all arthropods are insects.
Fish have single-loop circulation.
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.