What was the contribution of Oparin of Russia and Haldane of England regarding evolution?

Explanation

Both Oparin of Russia and Haldane of England proposed that the first form of life could have originated upon our earth spontaneously from non-living organic molecules (RNA, protein, etc.). Thus, formation of life was preceded by chemical evolution, i.e. formation of diverse organic molecules from inorganic constituents which evolved from inorganic compounds, under special environmental conditions prevalent at that time upon the earth.