Question

question 7
which of the following pairs is mismatched?
a methylene blue — positive stain
b nigrosin — negative stain
c basic dye — negative stain
d crystal violet — positive stain

Explanation:

Positive stains adhere to cells, and methylene blue and crystal violet are positive stains. Nigrosin is a negative - stain. Basic dyes are usually positive stains as they have a positive charge and bind to negatively - charged cell components, not negative stains.

Answer:

C. basic dye — negative stain