Why was it significant that amino acids were produced from a mixture of methane gas, hydrogen gas, ammonia, and water vapor?

It was significant because thanks to Miller's experiment, it was possible to test many years later and with modern techniques, the progress of the evolution of life on Earth.

Explanation:

In Miller's experiment, he subjected a mixture of methane, ammonia, hydrogen, carbon dioxide, nitrogen and water to strong electric shocks and high temperatures. He noted that organic molecules such as glucose, amino acids such as glycine, alanine, glutamic acid and aspartic acid were formed. Subsequently, in 2008 other scientists analyzed these compounds using more sensitive devices. Their analyzes found the formation of 20 amino acids (proteins) and 6 components found in the nucleus of the cells, thus checking the progress of the evolution of life on Earth.