do all animals who have antennas are arthropods?

Not all animals with antennae are arthropods, although antennae are a characteristic feature of this group. Antennae are sensory structures found in various animal phyla, including some mollusks and certain annelids. However, the presence of antennae is most commonly associated with arthropods, such as insects, crustaceans, and arachnids. Thus, while many animals with antennae are indeed arthropods, they are not exclusively so.