Final answer:
In preparation for Gram staining, a bacterial smear should be allowed to air-dry thoroughly before heat-fixing; staining with iodine is a subsequent step in the Gram staining procedure. the correct option is b) Air-dry in sunlight .
Step-by-step explanation:
When you pull the second slide apart from the first slide, let them air-dry in sunlight or dry naturally without using a heat source before proceeding with staining. The process described pertains to preparing a bacterial smear for Gram staining, a common technique used in microbiology to identify and classify bacteria. After smearing the bacterial culture onto a glass slide, it is crucial to allow the smear to completely air dry.
Afterwards, the slide is treated with various staining agents, including crystal violet and iodine, followed by alcohol decolorization and counterstain with safranin. It is only after these steps that you would proceed to stain with iodine, which is part of the Gram staining procedure to bind with the crystal violet and form a complex that gets trapped within the Gram-positive bacterial cell walls.