Chapter 4 - Nucleic Acids and the Origin of Life - 4.2 - The Small Molecules of Life Originated on Primitive Earth - 4.2 Recap - Learning Outcomes - Page 75: 1

The presence of O$_{2}$ in the atmosphere produces an oxidizing condition that prevents the reduction reactions, which would be observed in the Miller-Urey experiment.

The presence of O$_{2}$ in the atmosphere produces an oxidizing condition that prevents the reduction reactions, which would be observed in the Miller-Urey experiment.