A timeline of important discoveries about DNA is shown below. These discoveries have
contributed to our current knowledge about DNA.
1669
DNA is discovered.
1919
Base, sugar, and phosphate
structure is identified.
1944
1950
DNA identified as basis
of heredity.
Rules of nucleotide base
pairing established.
X-ray diffraction captures
DNA images
DNA structure is determined
1951
1953
Which statement best summarizes the development of knowledge of DNA over time?
Ideas about DNA have remained unchanged over time.
Scientists gained more knowledge about DNA as new evidence became available.
Changes in ideas about DNA are based on opinion.
Past knowledge of DNA was discarded as each new discovery was made.