Stanley Miller's experiments involved generating electrical sparks (simulating lightning) in a lifeless vessel containing hydrogen gas, water vapor, methane, and ammonia. The result was that . Stanley Miller's experiments involved generating electrical sparks (simulating lightning) in a lifeless vessel containing hydrogen gas, water vapor, methane, and ammonia. The result was that .

The correct option is;

a. Amino acids and other complex molecules formed in the vessel. This suggested that many of the organic building blocks of life could have arisen on a lifeless early Earth

Explanation:

In 1952 a chemical experiment simulating the conditions of the atmosphere of Earth during the early stages of existence, tested the chemical aspect of life's origin within the experimental condition. The experiment which represents the classic experiment of abiogenesis was carried out by Stanley Miller and Harold Urey at the University of Chicago.

In the experiment, "early ocean" was placed in a closed system along with hydrogen, ammonia.water vapor and after seven days amino acids such s alanine, aspartic acid glycine, which are organic chemicals prevalent in living tissue.