What is the invertebertes?

Answer 1

Invertebrates are animal species that do not develop a vertebral column. This in effect includes all animals apart from the subphylum Vertebrata. Familiar examples of invertebrates include insects, snails, and starfish. Taxonomically speaking "invertebrate" is no more than a term of convenience; only about 3% of animal species include a vertebral column in their anatomy.[1] In other words all animals except those in the chordate subphylum Vertebrata (fish, amphibians, reptiles, birds, and mammals) are regarded as invertebrates.

(source: Wikipedia)