How was the oxygen in the atmosphere produced?

Which of the following broke down water into hydrogen and oxygen on the early Earth?

What was the temperature maintained in Miller's experiment (in $^{\circ} C$)?

Stanley Miller had put the Oparin-Haldane theory to test in $1953$ by creating in the laboratory the probable conditions on the primitive earth. In the experiment,simple amino acids were synthesized from which of the following mixtures,as observed after eighteen days?

Life cannot originate from inorganic materials now because of

The early atmosphere contained methane and other hydrocarbons. They have now been replaced by: