Which of these is NOT an example of an invertebrate?

The correct response identifies a bird as not an example of an invertebrate. Invertebrates are animals that lack a backbone or vertebral column. This group includes creatures such as insects, spiders, and snails, all of which possess distinct characteristics and anatomical structures that categorize them as invertebrates.

Insects fall under the class Insecta, which includes a vast diversity of species, all lacking a backbone. Similarly, spiders belong to the class Arachnida and are well-known examples of invertebrates, characterized by their eight legs and absence of a spinal cord. Snails, falling under the class Gastropoda within the phylum Mollusca, also do not possess a vertebral column, thus classifying them as invertebrates.

Birds, however, belong to the class Aves and are characterized by having a backbone, which makes them vertebrates. This fundamental distinction between animals with and without backbones is essential for understanding biological classifications, making the identification of birds as vertebrates the correct choice in this context.