because they have no skeleton.
Mollusks compose of the large phylum of invertebrate animals known as the Mollusca. Mollusks have a mantle, mollusks invertebrate. Arthropods have jointed appendages, arthropods have segmented bodies
Arthropods have an exoskeleton. Mollusks don't.
a scorpion is a Arthropods
Vertebrates have spinal cords. Mollusks and arthropods do not.
Arthropods are more closely related to humans than mollusks. Both humans and arthropods belong to the larger group called Ecdysozoa, which is characterized by molting exoskeletons, while mollusks belong to a separate group called Lophotrochozoa. This evolutionary relationship places arthropods and humans closer on the tree of life.
Sponges, Cnidarians, Mollusks, and Echinoderms are not Arthropods.
A. Arthropods
sponges+mollusks+arthropods+worms+octopods+echinoderms
Flatworms, Roundworms, Annelids, Mollusks, and Arthropods
Lobsters are neither echinoderms nor mollusks like clams. They are also not arachnids. Instead, they are crustaceans, a subsection of arthropods.
There are over 50,000 known species of Mollusks! That figure makes them second only to the Arthropods in invertebrate phylum size.
No. Grasshoppers are arthropods. Mollusks are usually aquatic, and do not resemble insects.