Question

1. all amino acids contain oxygen, hydrogen, carbon, and nitrogen. identify the source of these elements on the early earth and in the urey-miller experiment.

Explanation:

On early Earth, these elements (oxygen, hydrogen, carbon, nitrogen) were present in the atmosphere and oceans. The atmosphere had gases like methane ($\ce{CH4}$) which has carbon and hydrogen, ammonia ($\ce{NH3}$) which has nitrogen and hydrogen. Water ($\ce{H2O}$) has hydrogen and oxygen. In the Urey - Miller experiment, they used a mixture of gases (water vapor ($\ce{H2O}$), methane ($\ce{CH4}$), ammonia ($\ce{NH3}$), and hydrogen ($\ce{H2}$)) to simulate the early Earth's atmosphere. Electric sparks were used to mimic lightning. Through chemical reactions, amino acids were formed. The hydrogen came from $\ce{H2}$ and $\ce{H2O}$, carbon from $\ce{CH4}$, nitrogen from $\ce{NH3}$, and oxygen from $\ce{H2O}$.

Answer:

On early Earth: hydrogen from water and hydrogen gas, carbon from methane, nitrogen from ammonia, oxygen from water. In Urey - Miller experiment: hydrogen from $\ce{H2}$ and $\ce{H2O}$, carbon from $\ce{CH4}$, nitrogen from $\ce{NH3}$, oxygen from $\ce{H2O}$.