Final answer:
The leukocyte with a large, kidney-shaped nucleus and 'frosted glass' cytoplasm is the monocyte, which is a type of agranular leukocyte. Unlike granular leukocytes, monocytes have less visible granules and are known for their phagocytic capabilities.
Step-by-step explanation:
The type of leukocyte described as having a large, kidney-shaped nucleus and 'frosted glass' cytoplasm is likely the monocyte. Monocytes are a type of agranular leukocyte with a simpler nuclear shape that sometimes shows an indentation, but without distinct lobes. This contrasts with granular leukocytes, such as neutrophils, eosinophils, and basophils, which typically have a lobed nucleus and are classified according to the type of stain that highlights their granules.
Monocytes, along with lymphocytes (another type of agranular leukocytes), contain smaller, less-visible granules within their cytoplasm compared to granular leukocytes. Monocytes are known for their role as large phagocytic cells that engulf foreign particles and pathogens. In a histological examination, their large nuclei and distinct cytoplasmic characteristics help in their identification.