Answer:
Answered below
Explanation:
In the 1920s, Russian Chemist A.I Oparan and English geneticist Haldane, first conceived and developed independently, the theory of Primordial soup. The primordial soup theory suggests that life began in a pond or ocean as a result of the combination of the right amounts of chemicals from the atmosphere and some form of energy, under the right conditions, which resulted in the production of amino acids, the building blocks of proteins from which life evolved. This is suggested to have happened 3 to 4 billion years ago.
This theory was tested by Chemist Stanley Miller and Physicist Harold Urey, in 1950. They mixed gases thought to be present in the primitive earth and electrically sparked the mixture, which resulted in the formation of amino acids.
War veterans returning from either Afghanistan or Iraq
