Question

george beadle and edward tatum developed a hypothesis known as “one gene– select choice .”

Explanation:

George Beadle and Edward Tatum's hypothesis is "one gene - one enzyme" (later revised to "one gene - one polypeptide" as understanding of proteins advanced, but the original key hypothesis is "one gene - one enzyme"). This is a concept in Biology (subfield of Natural Science) related to the relationship between genes and proteins (enzymes, initially).

Answer:

one enzyme