Living things are categorized or grouped based on their common characteristics. These characteristics can include factors such as their physical traits, anatomical features, genetic makeup, and reproductive strategies. By grouping living things based on these common traits, scientists can classify them into various levels of hierarchical classification systems, such as domain, kingdom, phylum, class, order, family, genus, and species. This system of classification is known as taxonomy and helps organize and understand the diversity of living organisms.
