the classification of organisms based on broad morphological characters
delimiting various taxa of organisms and establishing their relationships
the classification of organisms based on their evolutionary history and establishing their phylogeny, on the totality of various parameters from all fields of studies
identification and arrangement of organisms on the basis of their cytological characteristics
Solution
Biosystematics is the study of biological diversity and its origins. It focuses on understanding evolutionary relationships among organisms, species, higher taxa or other biological entities, such as genes and the evolution of the properties of taxa including intrinsic traits, ecological interactions, and geographic distributions. An important part of systematics is the development of methods for various aspects of phylogenetic inference and biological nomenclature. Whereas morphological characteristics (physical appearance) and cytological characteristics ( size of cell and nucleus) are not used for systematics. Thus, the correct answer is option (3).