● There are a millions of different animals around us with difference in their structure and form.
●In spite of these differences, there are many fundamental features common to various individuals, which are:
`star` Levels of organization of cells (Pattern of digestive, circulatory or reproductive systems within organ system organisation)
`star` Body Plan
`star` Body symmetry
`star` Nature of coelom
`star` Pattern of embryonic layers.
`star` Segmentation of the body
`star` Presence or absence of Notochord