The concept of chemical evolution is based on 

1. crystallization of chemicals

2. interaction of water, air, and clay under intense heat

3. effect of solar radiation on chemicals

4. the possible origin of life by the combination of chemicals under suitable environmental conditions

From his experiments, S.L. Miller produced amino acids by mixing which of the following in a closed flask:

1. ${\mathrm{CH}}_3,$ ${\mathrm{H}}_2,$ ${\mathrm{NH}}_4$ and water vapour at $800°\mathrm{C}$

2. ${\mathrm{CH}}_4,$ ${\mathrm{H}}_2,$ ${\mathrm{NH}}_3$ and water vapour at $600°\mathrm{C}$

3. ${\mathrm{CH}}_3,$ ${\mathrm{H}}_2,$ ${\mathrm{NH}}_3$ and water vapour at $600°\mathrm{C}$

4. ${\mathrm{CH}}_4,$ ${\mathrm{H}}_2,$ ${\mathrm{NH}}_3$ and water vapour at $800°\mathrm{C}$