QUESTION 9 Charles Darwin was the first person to propose a mechanism for evolution that was supported by evidence. a mechanism for how evolution occurs. that evolution occurs. that Earth is older than a few thousand years. QUESTION 10 Darwin's observation of the Galápagos Islands finches' various beaks and behaviors could be explained by adaptations forged by natural selection. adaptations to the specific foods available on their mainland. inherited traits that did not survive. modification with descent. QUESTION 11 Evolution must happen whenever a population is not well adapted to its environment. requires the operation of natural selection. can happen whenever any of the conditions for Hardy-Weinberg equilibrium are not met. must happen, due to organisms' innate desire to survive. QUESTION 12 For a repressible operon to be transcribed, which of the following must occur? RNA polymerase must bind to the promoter, and the repressor must be inactive. RNA polymerase and the active repressor must be present. A corepressor must be present. RNA polymerase cannot be present, and the repressor must be inactive.