If you go back in history approximately $4500$ million years,when the atmosphere was reducing,the organisms were:

Which gases were taken in the closed flask in $S$. $L$. Miller's experiment?

Which one of the following gases was not present in free form at the time life originated on Earth?

The theory of panspermia was proposed to explain the

Assertion : Organic compounds first evolved in earth required for origin of life were protein and nucleic acid.
Reason : All life forms were in water environment only.

Two statements regarding the origin of life are given below:
$(a)$ The first organisms that emerged on Earth are believed to have been devoid of chlorophyll and incapable of respiration.
$(b)$ The first food-producing organisms were chemosynthetic and never released oxygen.
Based on the above statements,which of the following options is correct?