Question

multiple select question
select all that apply
select all of the following characteristics of the flatworms, phylum platyhelminthes.
coelom
two germ layers
radial symmetry
protostome development
bilateral symmetry
three germ layers

Explanation:

• Coelom: Flatworms (phylum Platyhelminthes) are acoelomate, meaning they lack a coelom (a fluid - filled body cavity).
• Two germ layers: Flatworms have three germ layers (ectoderm, mesoderm, endoderm), not two. Organisms with two germ layers are diploblastic (e.g., cnidarians).
• Radial symmetry: Flatworms have bilateral symmetry. Radial symmetry is characteristic of cnidarians (e.g., jellyfish).
• Protostome development: Flatworms are protostomes. In protostome development, the blastopore (the opening of the archenteron in the gastrula stage) develops into the mouth.
• Bilateral symmetry: Flatworms exhibit bilateral symmetry, which allows for more directed movement and better organization of sensory organs at the anterior end.
• Three germ layers: Flatworms are triploblastic, having three germ layers (ectoderm, mesoderm, endoderm). The mesoderm gives rise to muscles and other internal organs.

Answer:

• protostome development
• bilateral symmetry
• three germ layers