Question

Miller synthesised simple amino acids from water vapours and mixtures containing:
A. Hydrogen, Oxygen, Nitrogen (1:2:1)
B. Hydrogen, Oxygen, Nitrogen (2:1:2)
C. Methane, ammonia, hydrogen (2:1:2)
D. Methane, ammonia, hydrogen (1:2:1)

Answer 1

Hint: Stanley L. Muller and Harold C. Urey carried out an experiment to define the origin of life on earth. They were of the idea that the early earth’s atmosphere could produce amino acids from inorganic matter. The two biologists took advantage of water, methane, ammonia, and hydrogen, which they considered were noticed in the early earth’s atmosphere.
Complete Step-by-step answer:

Miller and Urey provided the first proof for the chemical synthesis of proteins by amino acids. They simulated the primitive earth conditions as proposed by Oparin and synthesised simple organic chemical compounds (fatty acids sugars, amino acids, etc) from a mixture of hydrogen, methane, water vapour, and ammonia.

Miller presented the methane, ammonia, and hydrogen in the ratio of 2:1:2 in the high-energy chambers of his experimental device. With this ratio of gases, he can synthesise countless organic molecules which include amino acids.

As in the primitive atmosphere, hydrogen functioned as a reducing agent as methane provided a hydrocarbon skeleton for the synthesis of organic compounds. Water functioned as the medium for the chemical synthesis of organic substances in the glass chamber.

The primitive atmosphere was reducing and did not comprise oxygen or any oxide which makes carbon dioxide absent. The highly reducing primitive atmosphere did not have free nitrogen which was found in the form of ammonia only. 
Therefore the correct answer is Option C.
Note: Miller found an enormous number of simple organic substances including some amino acids like glycine, alanine, and aspartic acid. Glutamic acid was not found. Urey and Stanley Miller evaluated the Oparin-Haldane theory and successfully produced organic particles from some of the inorganic constituents thought to be present on prebiotic Earth.