The nurse correctly understands that the diphtheria toxoid is created by adding which substance to ...

Correct Answer: 3
Rationale 1: Yeast is not a part of vaccines, except for a slight relationship to the hepatitis B vaccine.
Rationale 2: Mercury has been removed from vaccines for safety's sake.
Rationale 3: Formalin is added to the diphtheria toxin to produce diphtheria toxoid.
Rationale 4: Mold is not added to any vaccines.
Global Rationale: Diphtheria toxin is produced by organisms in culture that are rendered inactive by the addition of formalin. Yeast is not a part of vaccines, except for a slight relationship to the hepatitis B vaccine. Mercury has been removed from vaccines for safety's sake. Mold is not added to any vaccines.

Makes a ton more sense now