Final answer:
Scientists use the cladistics system to organize monophyletic groups or clades, which include an ancestor and all of its descendants, to classify and understand evolutionary relationships.
Step-by-step explanation:
Scientists use the cladistics system to organize d. monophyletic groups. Cladistics is a method of organizing living things by their homologous traits, grouping organisms into clades, which are sets of species that share a common ancestor. In the process of constructing phylogenetic trees, clades must include all descendants from a branch point, indicating that these organisms share a distinct common ancestor. This approach contributes to the understanding of evolutionary relationships among organisms and supports the maintenance and updating of the "tree of life".
A clade is essentially synonymous with a monophyletic group, which implies that it includes an ancestor and all of its descendants. Scientists in the field of systematics utilize this information to classify and organize the diversity of life and to provide insights into the ways in which organisms are similar or different from each other based on their evolutionary history.