What does binomial nomenclature refer to?

Binomial nomenclature refers to the formal system of naming species using two specific terms. This system is used in biological classification to provide a unique name for each species, consisting of a genus name followed by a specific epithet. For example, Homosapiens designates the human species, where "Homo" is the genus and "sapiens" is the specific identifier. This two-part naming system helps ensure clarity and consistency in identifying and categorizing organisms globally, reducing confusion that might arise from regional names or common names that vary widely.

The other options don't align with the concept of binomial nomenclature; they pertain to different aspects of botany and biology, such as measurement, irrigation methods, or disease classification, which are not related to the naming of species.