Organisms that can be divided into mirror-image halves exhibit bilateral symmetry. This type of symmetry is significant in the evolution of many animals, allowing for streamlined bodies conducive to movement and interaction with their environment. Bilaterally symmetrical organisms typically have a defined head (or anterior) and tail (or posterior) end, which aids in directional movement and sensory processing. Common examples include vertebrates, arthropods, and many mollusks. This symmetry plays a key role in the development and organization of diverse body plans in the animal kingdom.