Final answer:
The reducing or developing solution is used in the Fontana-Masson histological staining technique to visualize melanin in tissues by reducing silver salts into visible silver particles.
Step-by-step explanation:
A reducing or developing solution is commonly used in histological techniques for staining biological tissues. In this context, the student is asking which technique utilizes such a solution. The correct answer is b. Fontana-Masson, which is used to visualize melanin in tissues. Fontana-Masson stain is a silver stain, and the reducing solution acts by reducing silver salts into visible silver particles in the presence of melanin, a pigment in the skin and other tissues.
A reducing chemical reaction can reduce the compound to a simpler form, add an electron to the substrate, remove a hydrogen atom from the substrate, or be a catabolic reaction. An example of a reduction process in a laboratory setting includes the use of a reduction column where an aqueous slurry of finely divided metal is packed in a glass tube to reduce substance passing through it.