Chapter 4 Animal Kingdom Part 1.

NCERT Class 11 Biology Chapter 4 classifies multicellular eukaryotic animals based on key diagnostic features that reflect evolutionary relationships: ​Basis of Classification: Categorized by levels of organization (cellular, tissue, organ, organ system), symmetry (radial, bilateral), germ layers (diploblastic, triploblastic), coelom presence, segmentation, and notochord.