Name of the scientist is S.L.Miller.
Purpose of 'a' is to supply electric discharge as a is a substitute of thundering.
Conclusion : Life originates from pre-existing life. It proved the chemical evolution of life.
Chemicals found in the samples drawn from 'c' sugar,proteins and amino acids.
It provided experimental evidences for the theory of chemical evolution of life. It proved that life originates from pre-existing life.