Question

which body symmetry is shown by adults in echinoderm?

Answer 1

Radial symmetry is shown by adult echinoderm

Answer 2

The Echinodermata are a major phylum of marine animals, and they provide many striking examples of inconsistencies between the apparent relationships of adults and larvae. These inconsistencies occur in attempting to assess the relatedness, first, of the echinoderms to other phyla, second, of classes within the echinoderms, and, finally, of several pairs of species within the same class.
Now
Adult echinoderms radially symmetrical, larvae bilaterally symmetrical--Conventional explanation assumes ancestral echinoderms bilaterally symmetrical throughout life but adults secondarily adopted radial symmetry.