In a set of classic experiments performed in the early 1950s, urey and miller subjected an experimental system composed of h2, ch4 (methane), and nh4 (ammonia) to electrical sparks. a few days later, they found in their system. a) microspheresb) cellsc) amino acidsd) rnae) dna

Explanation:

The idea of abiogenesis was proposed by the Oparin and Haldane which was later supported by the experiments of Urey and Miller. The thought that life originated from the abiotic molecules.

For this, they tried to create the same environment which was produced billions of years ago that is methane, ammonia, hydrogen gas and electric sparks.  

They found simple organic molecule like amino acids a few days after the experiment was performed. The amino acids are the building blocks of proteins.

Thus, Amino acid is the correct answer.

the truman doctrine was an american foreign policy whose stated purpose was to counter soviet geopolitical expansion during the cold war. it was announced to congress by president harry s. truman on march 12, 1947, and further developed on july 12, 1948, when he pledged to contain threats to greece and turkey.