Multiple choice How does base pairing take place after a tautomeric shift in guanine? Guanine pairs with cytosine. Guanine pairs with thymine. Guanine pairs with adenine. Guanine forms dimer with guanine. Reveal answer Fill a bubble to check yourself B Correct answer Explanation Due to tautomeric shift, the more stable keto form of guanine changes to less stable enol form and pairs with thymine.