Answer:
The correct answer is - a. The Porifera are asymmetrical, while the Cnidaria are radially symmetrical.
Step-by-step explanation:
In biology, symmetry f the body is meant the presence of a pair of organs in an orderly manner that if divide the body each part is a mirror of the other. In the phylum Porifera have asymmetric body plane.
Some animals develop into adults with radial symmetry. Cnidaria adults have radial symmetry type of body plans that eans if they are cut from the middle they divide in the two equal organs into both sides.