Ohio Assessments for Educators (OAE) Early Childhood Practice Exam

Which characteristic defines vertebrates among animals?

1. Possessing an exoskeleton

2. Having a segmented body

3. Having a backbone or spinal column

4. Being cold-blooded organisms

The correct answer is: Having a backbone or spinal column

Vertebrates are defined by the presence of a backbone or spinal column, which is a crucial characteristic that sets them apart from invertebrates. The backbone is made up of individual vertebrae that protect the spinal cord and provide structural support. This feature contributes to the overall organization and complexity of vertebrate bodies, allowing for greater mobility and flexibility compared to animals without a backbone. The presence of a backbone is integral to the group known as vertebrates, which includes mammals, birds, reptiles, amphibians, and fish. This defining trait not only characterizes the physical structure of these animals but also highlights their evolutionary adaptations and the roles they play in various ecosystems. In contrast, characteristics like possessing an exoskeleton or having a segmented body are associated with other groups of animals, such as arthropods and annelids, respectively. Being cold-blooded is a trait that applies to some vertebrates, but it does not universally define them, as there are also warm-blooded vertebrates. Thus, the presence of a backbone or spinal column is the critical characteristic that defines vertebrates among animals.