(N/A) Symmetry refers to the arrangement of body parts in relation to the central axis of an organism. Based on symmetry,animals can be categorized into three main types:
$1$. Asymmetrical: Animals cannot be divided into two equal halves by any plane passing through the center (e.g.,Sponges).
$2$. 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 (e.g.,Coelenterates,Ctenophores,and Echinoderms).
$3$. Bilateral Symmetry: When the body can be divided into identical left and right halves in only one plane,it is called bilateral symmetry (e.g.,Annelids,Arthropods,etc.).