What term refers to organisms with backbones and includes categories such as mammals and reptiles?

The term that refers to organisms with backbones is "vertebrates." Vertebrates are a subphylum of the phylum Chordata and are characterized by the presence of a vertebral column, commonly known as the backbone. This category includes a diverse range of animals such as mammals, reptiles, birds, amphibians, and fish. The backbone provides structural support and protection for the spinal cord, which is crucial for the nervous system and overall movement.

Understanding the characteristics of vertebrates helps to classify and differentiate them from other categories of animals, such as invertebrates, which do not possess a backbone. Thus, recognizing that vertebrates are specifically classified by this defining feature is essential in the study of animal biology.