30. the science of classification, or comparing, living and extinct organisms. a primatology b aboreality c. taxonomy dbrachiation

C. taxonomy

Explanation:

Taxonomy is the science of classification of nomenclature, classifying them based on a shared characteristic. Organisms are grouped into various taxas and ranked to fit the evolutionary phase of organisms. It is theory to represented by the practices grouping the individual species,  A field f science with systematic decision and identification of species. Classification of organisms based on the formation and analysis for classification. Thus its a science of the ordered arrangement of species on the earth.

81 is a composite number