Describe different types of Symmetry. 

Explanation

Animals can be categorised on the basis of their symmetry:
(1) Asymmetrical, (2) Radial symmetry, (3) Bilateral symmetry
(1) Asymmetrical : Sponges are mostly asymmetrical, i.e., any plane that passes through the centre does not divide them into equal halves.
(2) Radial Symmetry: When any plane passing through the central axis of the body divides the organism into two identical halves, it is called radial symmetry. Example : Coelenterates, ctenophores and echinoderms have this kind of body plan.
(3) Bilateral Symmetry : Animals like annelids, arthropods, etc., where the body can be divided into identical left and right halves in only one plane exhibit bilateral symmetry.