Why do biologists today use the three-domain system of classification?

Biologists use the three-domain system of classification because it provides a more accurate representation of the evolutionary relationships among organisms. This system is based on molecular data, particularly ribosomal RNA (rRNA) sequences, which offer a clearer understanding of the phylogenetic tree of life. The three-domain system acknowledges the distinct genetic and biochemical differences between prokaryotes and eukaryotes, leading to a more accurate classification of life forms.