Which of the following is used to distinguish between vertebrates and invertebrates?

The categorisation of the animal kingdom into two main groups invertebrate and vertebrate is mainly based on the presence or absence of a vertebral column (backbone).

Invertebrates do not have a backbone whereas, vertebrates possess a backbone along with an internal skeleton of bones or cartilage.

A few examples of invertebrates are sponges, hydra, flatworms, earthworms, insects, spiders, snails, starfish, etc.

A few examples of vertebrates are fishes, frogs, salamanders, lizards, snakes, birds, tigers, elephants, monkeys, humans, etc.