Which purine & pyrimidine bases are paired together by H bonds in DNA?
The correct option is B GC and AT
Purines and pyrimidines, make up the two groups of nitrogenous base
which plays on important role in structural backbone of DNA. Adenine and
guanine are purines, while cytosine and thymine are pyrimidines.
Purines pairs with pyrimidines, by formation of H-bonds. Adenine
attaches to thymine, by two hydrogen bonds, while cytosine and guanine
forms three hydrogen between them.