What taxonomy units do you know and what do they serve?

Studying different living organisms, people have long noticed that some of them have many similarities, while others are very different. Based on data on existing and extinct specimens, they began to be combined into taxa (classification categories). For example, the largest taxonomic link is the kingdom, within which organisms with common characteristics gather. The classes have already collected closer creatures, and the smallest link is the species. In between these three links, there are others.