Final answer:
A jellyfish exhibits radial symmetry, which is a body plan characterized by body parts arranged around a central axis, typical of the phylum Cnidaria.
Step-by-step explanation:
The type of symmetry exhibited by a jellyfish is radial symmetry. In radial symmetry, the arrangement of an organism's body parts is centered around a main axis. This allows an animal to experience the environment equally from all directions, which is highly beneficial for creatures like jellyfish that are often sedentary or have limited movement.
The body plan of jellyfish marks them as part of the phyla Cnidaria, among others like adult sea anemones, which also exhibit this form of symmetry. In contrast, animals like butterflies show bilateral symmetry, where there is only one plane that can divide the body into two mirror-image halves.