Answer: Proteinoid spheres
Explanation: Sidney W. Fox produced proteinoid spheres by heating the amino acids produced during the Miller-Urey Experiment.
Proteinoids can be defined as the substances that resembled protein. This substance was produced in the conditions that was created artificially that was very similar to the conditions that was formed during the time when life evolved on earth.
This did not proved that protein can be produced by heating of amino acids but further research can answer the process of various anabolic reactions.