The stage at which the described issue occurs is which?

• A. Flotation
• B. Mounting
• C. Staining
• D. Dehydration

Answer: (A)

The stage being tested is the flotation step, where paraffin sections are placed on a warm water bath to relax and flatten before mounting. This step is critical because the way a ribbon behaves on the water surface determines whether the tissue lays flat and wrinkle-free on the slide. If there’s an issue like wrinkling, curling, or tearing, it often points to the flotation process: water temperature that’s too cold or too hot, sections not being allowed to float and relax properly, or rough handling that stretches or tears the tissue. The remedy is gentle, controlled flotation in a properly warmed water bath, ensuring the sections settle flat and can be picked up with minimal tension onto clean slides, then dried before staining. Other stages—mounting, staining, and dehydration—operate on already prepared and processed tissue, so artifacts arising specifically from floatation are best explained by flotation technique.