The surface in the passage is described as changing from smooth to rough, just as the surface of a knee would change from smooth to rough while it was scabbing over and healing. A stripped screw would be an example of a surface changing its shape, but not from smooth to rough, so choice a is incorrect. Peaches and apples are different fruits with different surfaces, unlike the one surface that changes, making choice b incorrect. A cat’s reaction to a laser has nothing to do with the enhanced surface, so choice d is incorrect. An old tire’s tread would go from grooved to smooth, so choice e is incorrect.

Including how many people are affected by salmonella in the United States yearly further emphasizes how useful the development of the SERS will be after its completion. The author never criticizes the work of any institution, so choice a is incorrect. The author clearly supports the SERS project, but the second paragraph does not mention Parks’ research, so choice b is incorrect. The second paragraph does call attention to the problems salmonella creates, but its purpose is beneath the surface of the obvious, so choice c is incorrect. The second paragraph does not contain the main idea of the article, so choice e is incorrect.