What term is used to describe animals with a backbone?

The term that describes animals with a backbone is "Chordata." This phylum includes all vertebrates, which are characterized by having a spinal column or backbone made of vertebrae. These animals possess a notochord, a dorsal nerve cord, pharyngeal slits, and a post-anal tail during at least one stage of their development. Examples of chordates include mammals, birds, reptiles, amphibians, and fish.

In contrast, the other terms refer to different groups of animals. Invertebrates are animals that lack a backbone, encompassing a vast array of species. Echinoderms, such as sea urchins and starfish, are a specific group of invertebrates known for their radial symmetry and unique water vascular system. Arthropods, which include insects, arachnids, and crustaceans, are also invertebrates characterized by their exoskeleton and segmented bodies. Understanding these distinctions is crucial in the study of biology and animal classification.