They use heredity, fossils, early stages of development, and similarities they have between each other.
All of the above~!
Modern taxonomists use genetics to categorize living organisms.
to distinguish a group of things with similar characteristics e.g. mammals are all warm blooded, reptiles cold blooded.
It can be used it the library or supermarket
How to Use Triangles Classification
How to Apply Angle Classifications
The BYR Color Coded Wound Classification System
Learn About Classification of Quadrilaterals