This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Biochemistry
In DNA, Adenine pairs with 
Select and explain. 
A. Guanine, B. Thymine, C. Cytosine, D. Uracil
B: Thymine
Answer: B: Thymine 
Explanation: Adenine is always paired with thymine by formation of two hydrogen bonds. Guanine is always paired with cytosine by formation of three hydrogen bonds.