In what way are the body structure of fishes amphibians reptiles and mammals similar?

Fishes, amphibians, reptiles, and mammals share a basic vertebrate body plan characterized by a backbone, a skull, and a similar arrangement of muscles and bones. They all possess a central nervous system, limbs (or limb-like structures), and a circulatory system with a heart. Additionally, they exhibit bilateral symmetry, which means their body can be divided into mirror-image halves. Despite their adaptations to different environments, these structural similarities reflect their common evolutionary ancestry.