DNA is present as genetic material in all the living organism except some virus. DNA structure follows the Chargaff's rule in which states that the ratio of pyrimidines to purines is equal to 1.
So, amount of adenine will be equal to thymine. If adenine is 30% then thymine is also 30%. Total amount of DNA is 100%. Cytosine and thymine are also equal in the DNA molecule. The total amount of cytosine and guanine is 40%. The amount of cytosine is 20% and the amount of guanine is also 20%.
Thus, thymine is 30%, cytosine is 20% and guanine is 20%.
