Erwin Chargaff's work on the composition of nucleic acids began in 1944. His findings, which later became known
 Chargaff's rules, detail the specific pairings that occur in double-stranded DNA molecules.
 According to one of Chargaff's rules, a section of DNA molecule that contains 50 base pairs and has 15 adenine
 bases must also contain -
 A
 15 guanine bases
 B
 15 cytosine bases
 C 15 thymine bases
 D 15 uracil bases
 1-35
 Lark
 Daview/ind