Question

Which one of the following discoveries involving DNA happened first?

a. Chargaff discovered that base pairing was consistent in samples of DNA.
b. Griffith learned that a chemical changed harmless cells into harmful cells.
c. Avery discovered that DNA was responsible for storing and passing information through generations.
d. Hershey and Chase used bacteriophages to confirm that DNA was the genetic material in genes.

Answer 1

The answer is A.  Erwin Chargaff had discovered years earlier that the percentages of adelnine [A] and thymine [T] bases are almost equal in any sample of DNA.  It became the Charfaff's Rule.  However, no one knew why they did.