This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General pathology, Subject name: Pathology
The feulgen reaction is used to test 
Select and explain. 
A. mRNA, B. tRNA, C. DNA, D. rRNA
C: DNA
Answer: C: DNA 
Explanation: *Feulgen stain is a staining technique to detect DNA *In this procedure, the specimen is exposed to warm HCL which causes hydrolysis of DNA to produce aldehyde. Then Schiff reagent is added which reacts with aldehyde to impa red colour.