IB Biology Exam Prep

Answer: E, genus. Genus is the sixth level of classification, only followed by species.

Key Takeaway: The classification of organisms follows the following sequence: kingdom, phylum, order, class, family, genus, species. At the top of the classification, organisms only share general features. For example, all members of the Kingdom Animalia are eukaryotes, which differentiates them from bacteria. With each level down the classification system, organisms share more and more in common, thus reducing the number of species in each classification.