(N/A) The classification of Kingdom Animalia is based on several fundamental features of animals,which are as follows:
$1$. Levels of Organization: Animals exhibit different levels of organization,such as cellular level,tissue level,organ level,or organ-system level.
$2$. Symmetry: Animals can be asymmetrical,radially symmetrical,or bilaterally symmetrical.
$3$. Diploblastic and Triploblastic Organization: Based on the number of germ layers,animals are classified as diploblastic (two layers: ectoderm and endoderm) or triploblastic (three layers: ectoderm,mesoderm,and endoderm).
$4$. Coelom (Body Cavity): The presence or absence of a cavity between the body wall and the gut wall is crucial. Animals are classified as acoelomates (no body cavity),pseudocoelomates (false body cavity),or coelomates (true body cavity).
$5$. Segmentation: In some animals,the body is externally and internally divided into segments with a serial repetition of at least some organs (metamerism).
$6$. Notochord: The presence or absence of a notochord is a significant feature used to distinguish between non-chordates and chordates.