Question

staining • spore staining
laboratory simulation
labels
primary stain
sample/dye penetrant
secondary stain

rinse water
heat-fixed bacterial smear
microscope
blotting paper

Explanation:

Identify the laboratory simulation context

The image shows a laboratory simulation interface for "STAINING • SPORE STAINING" (endospore staining). On the left, there are three draggable labels: "Primary stain", "Sample/dye penetrant", and "Secondary stain". On the workbench, there are orange target indicators pointing to specific items.

Match labels to reagents and methods

1. The first indicator points to the bottle labeled "Malachite Green". In endospore staining (Schaeffer-Fulton method), Malachite Green is the primary stain.
2. The second indicator points to the beaker on the hot plate, which is used to apply heat/steam. Heat acts as the mordant or penetrant to force the malachite green into the resistant endospore coat. Thus, heat/steam is the sample/dye penetrant.
3. The third indicator points to the bottle labeled "Safranin". Safranin is used as the counterstain or secondary stain to color the vegetative cells.

Answer:

Label	Target Item
Sample/dye penetrant	Heat (Beaker on hot plate)
Secondary stain	Safranin