Answer: James Watson and Francis Crick
Step-by-step explanation:
In 1953 James Watson and Francis Crick are responsible for determining the structure of DNA. James and Watson proposed that the DNA is made up of a double polynucleotide chains that are twisted around each other to forming a helical structure. The two DNA chains runs anti-parallel in opposite direction to each other. Like the structure of the ladder.
The answer is James Watson and Francis Crick