Final answer:
Gastropods experience torsion during embryonic development, rotating their visceral mass and repositioning their organs, including the opening above the head. This process is true and distinguishes gastropods, such as snails and slugs.
Step-by-step explanation:
Gastropods, which include familiar creatures such as snails and slugs, undergo an embryonic development process known as torsion. This process involves the counterclockwise rotation of the visceral mass, effectively moving the opening to a position above the head, resulting in asymmetry within the animal's body and a repositioning of organs. Furthermore, torsion is distinct from shell coiling and is a defining feature of gastropods, affecting their bilateral symmetry. It is a peculiar developmental stage that leads to a unique anatomical configuration; however, some evolutionary lines within the group have reversed this feature.
Therefore, the correct statement is that gastropods undergo torsion as they develop, which is True.