Note the rhetorical shift indicated by "But..." in sentence 6. What is its purpose and effect?

Answer and Explanation:

President Abraham Lincoln delivered the speech now known as the "Gettysburg Address" in 1863, in a battlefield near Gettysburg, Pennsylvania.

Lincoln says they are gathered there in order to dedicate "a portion of that field" to those who have sacrificed their lives in the war. However, immediately after saying that, his speech shifts, beginning by the word "but". This word indicates a change in path, so to speak, for his ideas to follow. He basically contradicts himself by now saying that it is impossible to consecrate that field, and he provides two reasons for that. First, the field has already been consecrated by the blood of those who lost their lives. Second, because the greater struggle is not over yet. The war was still raging, and so those who were alive had the duty to keep on fighting, so that the fallen soldiers wouldn't have lost their lives in vain.

the answer is:

b) to show the progression of inventions that took place in the bicycling industry.

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