Biochemistry The term modified base refers to A Purine or pyrimidine attached to deoxyribose B A purine or pyrimidine that has been altered C A nitrogen containing ring other than a purine or pyrimidine that is part of a nucleotide D A purine or pyrimidine attached to a sugar by O-glycoside linkage 💡 Explanation The term modified base refers to ✓ Correct Answer: B. A purine or pyrimidine that has been altered