Which one of the following has a bilateral symmetry in its body organization?
A
Asterias
B
Sea anemone
C
Nereis
D
Euchinus
Correct Answer: Asterias
Asterias has bilateral symmetry only at larval stagebut fivefold symmetry (pentamerism, a special type of radial symmetry) as adults.
Nereis do not possess any symmetry elements in their body organisation.