Some organisms that are alive today do not look exactly like organisms that lived in the past. however, if a comparison of dna samples from two organisms that differ in appearance reveals that the organisms are nearly genetically identical, the samples may be used as evidence for : a. the big bang theory, or the theory that life began as a clump of matter that exploded outwards. b. atomic theory, or the theory that atoms are the most basic units of matter. c. the theory of evolution, or the theory that characteristics of populations can change over time. d. cell theory, or the theory that cells are the most basic units of life.