Concept: Binomial nomenclature is the formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin grammatical forms, although they can be based on words from other languages. This system was popularized by Carl Linnaeus.
Step 1: Understanding Binomial Nomenclature
The term "binomial" itself means "two names." In this system:
The first part of the name identifies the Genus to which the species belongs.
The second part of the name identifies the specific epithet or species name within that genus.
Together, these two parts form the unique scientific name of a species.
Step 2: Rules for Writing Binomial Names
The genus name is always capitalized.
The species epithet is always written in lowercase.
Both names are usually italicized when typed, or underlined when handwritten.
Example: The binomial name for humans is {Homo sapiens}.
{Homo} is the genus name.
{sapiens} is the specific epithet (species name).
Step 3: Analyzing the options
(1) Phylum and class: These are higher taxonomic ranks in the biological classification system (Kingdom>Phylum>Class>Order>Family>Genus>Species). Not the two parts of a binomial name.
(2) Class and genus: Also higher and lower taxonomic ranks, not the two parts of the species name.
(3) Genus and species: Correct. The binomial name consists of the Genus name followed by the species epithet.
(4) Phylum and species: Incorrect combination.
The handwritten "G S" (Genus, Species) on the image also indicates this correct pairing.
Therefore, the binomial nomenclature is made up of the Genus and species names.