What is the role of aliphatic hydrocarbons in tissue processing as described?

• A. Clearing
• B. Dehydration
• C. Embedding
• D. Staining

Answer: (A)

Clearing is the step that bridges dehydration and embedding. After tissue is dehydrated with alcohol, a clearing agent—an aliphatic hydrocarbon—treats the tissue to remove the alcohol and, crucially, to be miscible with molten paraffin wax. This makes the tissue transparent and enables paraffin to infiltrate the tissue fully, so it can be embedded and support thin sectioning. Staining happens later, on sections, and dehydration or embedding don’t perform this solvent transition. The aliphatic hydrocarbon’s role is precisely to replace the alcohol and prepare the tissue for paraffin infiltration.