AP BIOLOGY

Detailed explanation-1: -Due to Urey’s hypothesis, Miller did not include oxygen as part of his experiment. He placed hydrogen, boiling water, methane and ammonia into an enclosed chamber (chem.duke.edu).

Detailed explanation-2: -Miller Urey excluded Oxygen from the mixture of gases in their experiment as they knew that that Oxygen would make the formation of organic molecules from non organic molecules impossible.

Detailed explanation-3: -The study shows that Miller–Urey experiments produce RNA nucleobases in discharges and laser-driven plasma impact simulations carried out in a simple prototype of reducing atmosphere containing ammonia and carbon monoxide.

Detailed explanation-4: -In a reducing atmosphere, hydrogen is present but oxygen is absent. For the Miller-Urey experiment to work, a reducing atmosphere is a must.