Why do snails undergo torsion?

Snails undergo torsion as a developmental process that helps align their internal organs and nervous system. During this process, their body twists 180 degrees, positioning the anus above the head. This adaptation allows for a more compact body structure, which is beneficial for their movement and habitat. Additionally, torsion may help snails retract into their shells for protection, ensuring that their sensitive body parts are shielded from predators.