Question

Stanley Miller synthesized ---------in his experiment.
A. Virus
B. Proteins
C. Amino acids
D. Cells

Answer 1

Hint: Stanley Miller in their experiment in the laboratory predicted on the proto -Earth. He observed the formulation of glycine, alanine and aspartic acid.

Complete step-by-step answer:
To explain the origin of life Stanley conducted an experiment. They had the belief that the atmosphere of the earth is capable of extracting amino acids from inorganic matter. In the early s atmosphere the two biologists used methane, water, hydrogen and ammonia, which they thought to have been discovered.
                                             

                                                               Stanley Miller Experiment setup
Inside the sterile glass tubes the chemicals were sealed and flasks were sealed and flasks attached together in a loop and circulated inside the apparatus. One flask is half filled with water and a pair of electrodes is used in other flasks.
The water vapour has been heated and the released vapour has been applied to the chemical mixture. The emitted gases dispersed throughout the apparatus mimicking the atmosphere on the earth.
The water in the flask reflects the water on the surface of the planet and water vapour is much likely like the water that evaporates from the seas and lakes.
To ignite the fire, the electrodes are used to mimic lightning and storm by water vapour. It cooled the vapour and condensed the water.
In a continuous cycle this condensed water trickles back into the water container.
After a week he analysed the cooled water and noticed that 10-15 percent of carbon was in the form of organic compound. 13 amino acids were produced by 2 percent of carbon.

Therefore the correct answer is C

Note:
The main purpose of Miller's experiment was to test the hypothesis which states that the complex molecules of life, amino acids have arisen through simple, natural chemical reactions on our young planet. The experiment by Miller proved that amino acids are the building blocks of life and were formed at the simulation of the circumstances of Earth’s atmosphere. For the lightening effect Millar has kept some electrodes that were present for the spark discharge.
Therefore he synthesized more quantities of glycine, alanine, and aspartic acid while glutamic acid is not synthesized in his experiment.