Stanley Millerand Harold Urey synthesized amino acid by passing an electric discharge in a mixture of ammonia $\left( NH _{3}\right), A=\pi r^{2}$ hydrogen $\left( H _{2}\right)$ water vapours $\left( H _{2} O \right)$ and methane $\left( CH _{4}\right) .$ The ratio of $CH _{4}, NH _{3}$ and $H _{2}$ in large flask was $2: 1 : 2$