Invertebrate

Invertebrate explained in an easy to understand way:

Imagine trying to build a house of cards on a slightly uneven table. Without a stable foundation, the cards can easily topple over, much like how invertebrates lack the rigid backbone that vertebrates rely on for structural support. Just as the table's uneven surface leaves the house of cards unsupported and vulnerable, invertebrates are animals that function without the internal backbone, instead relying on other structures or their environment to maintain their form.