A scientist who was directing a closely watched study on genetically engineered crops at the high-profile National Academy of Sciences abandoned his post last month for a job in the biotech industry, giving weight to fears of environmental scientists that the final report will be biased toward the industry’s point of view. The study, intended to be a comprehensive look at the risks and benefits of genetically modified crops, is expected to have a significant effect on how the federal government decides to regulate the crops. Meanwhile, public opinion in the U.S. toward genetically engineered foods is shifting, with Americans starting to call for the foods to be labeled.