What was Friedrich Miescher's contribution to the discovery of the genetic code?

A) He created the first photograph of the structure of DNA.

B) He discovered how the DNA bases pair together.

C) He created the first accurate model of DNA's structure.

D) He extracted and observed DNA from white blood cells.

The best answer is D. He extracted and observed DNA from white blood cells. He is a Swiss physician and a biologist who is known to be the first researcher to identify nucleic acid. He isolated various phosphate-rich chemicals, which he called nuclein or what we know now as nucleic acid, from white blood cells' nuclei which paved the way for him to discover and identify DNA.