Define the following terms:
$(i)$ Bilateral symmetry
$(ii)$ Diploblastic

(N/A) $(i)$ Bilateral symmetry: It is a type of body organization in which the body can be divided into identical left and right halves only in one plane.
$(ii)$ Diploblastic: Animals in which the cells are arranged in two embryonic layers,an external ectoderm and an internal endoderm,are called diploblastic animals. In addition,an undifferentiated layer called mesoglea is present between the ectoderm and the endoderm,e.g.,$Coelenterates$.