Platyhelminthes show cephalization, meaning they have what?

Platyhelminthes show cephalization, meaning they have what?

• A. CNS - Brain
• B. Endoskeleton
• C. Gastrovascular Cavity
• D. Digestive System

Answer: (A)

Cephalization refers to the concentration of nervous tissue at the anterior end to form a head region, including a brain-like center. In flatworms (Platyhelminthes), this shows up as a pair of cephalic ganglia at the head connected to longitudinal nerve cords, creating a simple central nervous system. This centralized nervous tissue is what cephalization describes—a primitive brain region that helps process sensory input and coordinate movement. It does not indicate an internal skeleton, and while flatworms do have digestive structures like a gastrovascular cavity or gut, those features aren’t what cephalization defines.

Cephalization refers to the concentration of nervous tissue at the anterior end to form a head region, including a brain-like center. In flatworms (Platyhelminthes), this shows up as a pair of cephalic ganglia at the head connected to longitudinal nerve cords, creating a simple central nervous system. This centralized nervous tissue is what cephalization describes—a primitive brain region that helps process sensory input and coordinate movement. It does not indicate an internal skeleton, and while flatworms do have digestive structures like a gastrovascular cavity or gut, those features aren’t what cephalization defines.