Question

which phylum is mainly asymmetrical? cnidaria porifera (sponges) echinodermata arthropoda

Explanation:

To determine the mainly asymmetrical phylum, we analyze each option:

• Cnidaria: Often exhibit radial symmetry.
• Porifera (sponges): Most sponges are asymmetrical, as they lack a definite symmetry plan.
• Echinodermata: Typically have pentaradial symmetry (a type of radial symmetry in adults).
• Arthropoda: Usually have bilateral symmetry.

So, Porifera (sponges) is the phylum that is mainly asymmetrical.

Answer:

B. porifera (sponges)