Igive you a tube with water, dopa, ppo, but no buffer. will there be color change?

If I were given a tube of water, dopa, ppo but with no presence of buffer, there will be a color change. But if you were to give me the following with a presence of buffer, then there will be no color changing occurred.

in 1859, charles darwin set out his theory of evolution by natural selection as an explanation for adaptation and speciation. he defined natural selection as the "principle by which each slight variation [of a trait], if useful, is preserved".