Which was absent in the atmosphere at the time of origin of life ?

Which was absent is the atomospher at the time of origin of life ?

Which was absent is the atmospher at the time of origin of life ?

Which gas was absent in the atmosphere at the time of origin of life?

Which was absent/least abundant in the atmosphere at the time of origin of life?

Which was absent/least abundant in the atmosphere at the time of origin of life?

The following gas was most likely absent from the primordial atmosphere at the time of origin of life

Which of the following was most likely to have been absent in free form in the primordial atmosphere at the time of origin of life Or Miller performed experiment to prove molecular evolution of life. Which molecule was not present in Miller's experiment

The gas which was absent in the environment during the origin of life is

Which gas was absent in the atmosphere of primitive earth?