You can categorize every single living being. This classification system allows scientists to study plant and animal diversity and to group closely related species. From horses to insects to worms, ...

There are millions of different types of living things on Earth. In order to keep track of them all, scientists put living things into groups based on characteristics that they have that are the same.

Classification is a natural human propensity—we organize our clothes, our kitchen cupboards, and our toys. This applies to the natural world, too, where animals and plants are grouped based on ...