Describe Chargaff rule.

Explanation

Use of `.^(15)N` will be inappropriate because method of detection of `.^(35)P` and `.^(15)N` is different (`.^(32)P` being a radioactive isotope while `.^(15)N` is not radioactive but is the heavier isotope of Nitrogen). Even if `.^(15)N` was radioactive then its presence would have been detected both inside the cell (.^(15)N` incorporated as nitrogenous base in DNA) as well as in the supernatant because 'N would also get incorporated in amino group of amino acids in proteins). Hence the use of `.^(15)N` would not give any conclusive results.