Final answer:
According to Chargaff's rules, in DNA, the amount of adenine is equal to thymine, and the amount of guanine is equal to cytosine. Since the nucleic acid contains 32% adenine, guanine would account for 18 percent of the nucleic acid.
Step-by-step explanation:
If a nucleic acid was analyzed and found to contain 32 percent adenine, to determine the percent of guanine in the nucleic acid, we need to apply Chargaff's rules. These rules state that in DNA, the amount of adenine (A) is equal to the amount of thymine (T), and the amount of guanine (G) is equal to the amount of cytosine (C).
Since adenine makes up 32% of the nucleic acid, thymine would also make up 32%, accounting for a total of 64% for both adenine and thymine. This means the remaining 36% must be divided equally between guanine and cytosine. Consequently, guanine would represent 18 percent of the nucleic acid. Therefore the answer is option a) 18%.