Biologists have described well over a million species of eukaryotes.Most species that have been described are known primarily by their
A) DNA sequence information.
B) gene expression data.
C) fossil record.
D) morphology.
E) behavior.

Question

Quizplus · Accepted Answer

Morphology, or physical appearance and structure, has traditionally been the primary method for identifying and describing species. While DNA sequence information and gene expression data can be used in combination with morphology to distinguish between closely related species, these methods are not yet widespread enough to have characterized most of the known eukaryotic species. The fossil record can be used to trace the evolutionary history of species, but is less helpful in identifying individual organisms themselves. Behavior, while useful for studying certain aspects of an organism's ecology, is often variable within a species and therefore not a reliable tool for species identification.

Biologists Have Described Well Over a Million Species of Eukaryotes