Question

In which of the following, does torsion occur?
(1) Pila
(2) Periplaneta
(3)Pheretima
(4)Physalia​

Answer 1

Answer:

gastropods

Explanation:

Torsion is the rotation of the visceral mass and foot 180 degrees with respect to the head and foot, and is a unique synapomorphy of modern gastropods. Torsion occurs during development in all gastropods, usually in the late veliger stage. However, some gastropods do not remain torted when becoming adults.

Torsion is a gastropod synapomorphy which occurs in all gastropods during larval development.