Final answer:
The vertebrae is not an irregular bone; it belongs to the category of irregular bones due to its distinct shape and structure.
Step-by-step explanation:
The vertebrae is not an irregular bone. Irregular bones, such as the vertebrae and the bones of the skull, have complex and unique shapes that don't fit into any of the other bone categories. However, the vertebrae are considered as irregular bones due to their distinct shape and structure. They have a ring-like structure with a central body and various processes extending from it.
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