Which term denotes a taxonomic level used in classification that groups related organisms?

• A. Hypertonic
• B. Isotonic
• C. Hypotonic
• D. Heterotroph

Answer: (B)

In biology, taxonomy classifies organisms using hierarchical levels that group related organisms based on shared ancestry and characteristics. The terms hypertonic, isotonic, and hypotonic describe how solutions compare in solute concentration and affect water movement across membranes, not how organisms are related. Heterotroph describes how an organism obtains its carbon—nutrition mode—again not its place in the classification hierarchy. So, none of these terms denote a taxonomic level like genus or family, which are the ranks used to group related organisms. Remember that taxonomy focuses on evolutionary relationships, and a common reminder of the ranking order is the mnemonic that helps recall domain, kingdom, phylum, class, order, family, genus, species.