Answer:
The correct answer is : lack of molecular evidence.
Step-by-step explanation:
The Linnaean classification system was depended on clear physical qualities. It comprises of a chain of command of taxa, from the kingdom on the top to the species as more specific taxa. Every species is given a one of a kind two-word Latin name. The system is based completely on physical characteristics of organisms, due to lacking the proper technology to investigate the molecular data of animals .
Thus, the correct answer is : lack of molecular evidence.