Final answer:
Flatworms feature a bilateral symmetry body plan, which permits division into mirrored right and left sides. This accompanies other characteristics like an incomplete digestive system and a centralized nervous system in the head region, enhancing their survival and ability to move efficiently.
Step-by-step explanation:
The flatworm exhibits a specific type of body symmetry that is characteristic of its phylum. While it does not have body cavities or complex organs, it presents a definite body plan. A flatworm has bilateral symmetry, meaning that its body can be divided along a single plane into two mirrored halves - a right and a left side. This body plan is accompanied by other features such as an incomplete digestive system, a ladder-like nervous system, and in most cases, a distinct head region referred to as cephalization.
Bilateral symmetry is often contrasted with radial symmetry, where any plane along the longitudinal axis can divide the organism into equal halves, and asymmetric organisms which have no definite pattern. The evolutionary benefit of bilateral symmetry in flatworms is significant, allowing for streamlined movement and a structured nervous system, which aids in survival and adaptation.