What is the three domain system BBC Bitesize?

The three-domain system, as explained by BBC Bitesize, is a method of classifying living organisms into three broad groups: Archaea, Bacteria, and Eukarya. This classification is based on differences in the sequences of ribosomal RNA (rRNA), a type of genetic material found in all living cells. The system was introduced by Carl Woese in 1990 and provides a more accurate representation of evolutionary relationships among organisms compared to previous classification systems.