Answer
(a) for the cytoplasm; (b) for the flagella
Work Step by Step
In both cases, mordant is used in order to help ensure that the stain will bond to the specimen: this ensures that the specimen is clear when the viewer looks at it. In the case of gram stain, mordant allows the cytoplasm to be more easily seen, and in the case of the flagella stain, it allows the flagella to be more easily seen.
