What structural problem prevents adenine from pairing with guanine? Naim 01:38 Biology What structural problem prevents adenine from pairing with guanine? a. The bases are both short b. They lack phosphate groups. c. They lack the deoxyribose group. d. The bases are both long. Answer: d. The bases are both long. Learn More : Share this Share on FacebookTweet on TwitterPlus on Google+