Which one of the following groups of animals is bilaterally symmetrical and triploblastic ?
Which one of the following groups of animals is bilaterally symmetrical and triploblastic ?
Sponges
Coelentrates (Cnidarians)
Aschelminthes (round worms)
Ctenophores
Solution
Aschelminthes (round worms) are bilaterally symmetrical and triploblastic.
Bilaterally symmetrical means their body can be divided into two equal halves along one plane.
Triploblastic means they have three germ layers: ectoderm, mesoderm, and endoderm.
Other groups:
Sponges are asymmetrical and diploblastic (lack mesoderm).
Coelenterates (Cnidarians) are radially symmetrical and diploblastic.
Ctenophores are radially symmetrical and diploblastic.