Question

question 6 (4 points) listen give an example and describe the basic structure of the platyhelminthes.

Explanation:

Platyhelminthes are flatworms, a group of acoelomate, bilaterally symmetrical invertebrates. A common example is the planarian (Dugesia). Their key structural traits include a flattened, unsegmented body, no true body cavity (acoelomate), a gastrovascular cavity for digestion (with a single opening serving as mouth/anus), and a primitive nervous system with ganglia and nerve cords. They also have specialized cells for osmoregulation (flame cells) and are often hermaphroditic.

Answer:

Example: Planarian (Dugesia)
Basic structure:

1. Bilaterally symmetrical, flattened, unsegmented body
2. Acoelomate (no true body cavity)
3. Gastrovascular cavity (incomplete digestive system with one opening)
4. Primitive nervous system (cerebral ganglia + nerve cords)
5. Flame cells for osmoregulation
6. Hermaphroditic reproductive system