Item I. If the amount of G in a double helix is known, the amount of C can be calculated

Item II. If the fraction of purine nucleotides and the total molecular weight of a double helix are known, the amount of cytosine can be calculated.

Item III. The two chains in a piece of ds-DNA containing mostly purines will be bonded together more tightly than the two chains in a piece of ds-DNA containing mostly pyrimidines

Item IV. The oligonucleotide ATGT AT is complementary to the oligonucleotide AT ACA T.