Which of the following is a scientific name?

• A. Streptobacilli
• B. Gram-positive streptococcus
• C. Anthrax
• D. Streptococcus pyogenes

Answer: (D)

Binomial nomenclature uses a two-part Latin name to identify a species: the genus name followed by the species epithet, together uniquely naming the organism. The correct name, Streptococcus pyogenes, fits this format exactly—the genus Streptococcus is capitalized and the species epithet pyogenes is lowercase, and the pair is written in Latin (usually in italics). This precise, universally used naming lets scientists know exactly which organism is being referred to, avoiding confusion with common names or descriptive terms.

The other options aren’t scientific names in this two-part format. Streptobacilli is not a proper binomial name. Gram-positive streptococcus is a descriptive phrase about appearance and staining, not a formal genus–species name. Anthrax is a disease name (or common usage), not the species’ binomial designation. So, Streptococcus pyogenes is the valid scientific name.