Which of the following statements correctly defines a simple stain?

Which step in the Gram staining process is crucial for differentiating between gram-positive and gram-negative bacteria, and what would happen if it were omitted?

What characteristic of mycolic acid in acid-fast bacteria makes them resistant to decolorization by acid-alcohol?

What is the primary stain used in the endospore staining method?

In an experiment using immunofluorescence, a researcher observes unexpected fluorescence in control samples lacking the target antigen. What could be a plausible explanation for this result?