Flatworms are the first organisms we have discussed with an anterior-posterior orientation. How does this affect their movement compared to the movement of more primitive organisms

Anterior-posterior orientation

Explanation:

Flatworms have an anterior-posterior orientation and as a result more coordinated and deliberate movement is established  

Flatworms also called Platyhelminthes are a phylum of relatively simple soft-bodied invertebrate animalsThey are the largest phylum of acoelomates and are found in marine,freshwater and even in some damp terrestrial environmentsMovement in some flatworms is controlled by longitudinal,circular and oblique layers of muscleFlatworms anterior end helps in moving towards their food while the posterior end ensures that these organisms walk away from irritants