U fiirso qoraalka hoose ka dibna ka jawaab su'aasha kadib isla luqadda qoraalka:  Qaabka loo kala saaro noocyada dhirta ayaa weli is bedelaya. Kala soocida cusub waxay isku dayaan inay soo bandhigaan kooxo monophyletic ah oo ku saleysan morfological (gaar ahaan ultrastructural), biochemical (chemotaxonomy) iyo DNA taxane (cilmi baaris molecular) macluumaad. Si kastaba ha noqotee, mararka qaarkood waxaa jira khilaafyo u dhexeeya cilmi baarista molecule-ka iyo morfolojiga; Kuwani waxaa loo kala saari karaa laba nooc: (i) hal morfoloji, hiddo-wadaha badan (tusaale ahaan is-dhexgalka morfolojiga, noocyada qarsoon) iyo (ii) hal hiddo-wadaha, hiddo-wadaha badan (tusaale ahaan caagista phenotypic, marxaladaha wareegyada nolosha badan). Sababtoo ah protists-ka guud ahaan waa paraphyletic, nidaamyada cusub ayaa inta badan kala qaybsama ama ka taga boqortooyada, halkii ay ula dhaqmayaan kooxaha protist-ka sida khadadka eukaryotes. Qorshaha dhawaan ay sameeyeen Adl et al. (2005) ma aqoonsana darajooyinka rasmiga ah (phylum, class, iwm.) oo taa bedelkeeda waxay ula dhaqmaan kooxaha sida kooxaha noolaha ku saabsan hiddo-wadaha. Tan waxaa loogu talagalay in lagu sameeyo kala soocida mid xasilloon muddo dheer iyo in la fududeeyo cusbooneysiinta. Qaar ka mid ah kooxaha ugu waaweyn ee protists, kuwaas oo loo tixgelin karo sida phyla, ayaa ku taxan sanduuqa, midigta sare. Qaar badan ayaa loo malaynayaa inay yihiin monophyletic, in kasta oo weli aan la hubin. Tusaale ahaan, Excavata waxaa laga yaabaa inaysan ahayn monophyletic iyo chromalveolates waxaa laga yaabaa inay yihiin monophyletic kaliya haddii haptophytes iyo cryptomonads la saaro.  Su'aal: Waa maxay mid ka mid ah astaamaha Excavata?
aan ahayn monophyletic