Which of the following statements regarding a DNA double helix is true? The amount of adenine is equal to the amount of thymine, and the amount of guanine is equal to the amount of cytosine. The amount of adenine is equal to the amount of uracil, and the amount of guanine is equal to the amount of cytosine. The amount of adenine is equal to the amount of guanine, and the amount of thymine is equal to the amount of cytosine. The amount of adenine is equal to the amount of guanine, and the amount of uracil is equal to the amount of thymine. The amount of adenine is equal to the amount of cytosine, and the amount of guanine is equal to the amount of thymine.

DNA (deoxyribo nucleic acid ) is the genetic material present in all the organisms except some viruses. DNA structure follows the Chargaff's rule.

Accoprding to Chargaff's rule, the ratio of purines to pyrimidines in a DNA molecule is equal to 1. The amount of guanine is nearly equal to the amount of cytosine whereas the amount of thymine is nearly equal to the amount of adenine.

Thus, the correct answer is option (1).