I read many articles on-line, but cannot understand where to draw the line between expository and argumentative writing. According to many articles, expository writing presents information. Argumentative writing tries to argue a case.
Every research paper I have ever read has some form of argument in it. That is their thesis. They might be arguing, "This new veterinary medicine we tested did not conclusively cure the disease in cats", then they present the data from the study. Or they might argue "Our new method for extracting coal works very efficiently," and then present their research data proving this argument. Since the authors are arguing the case for something, even with the scientific method behind it, does that make it an argumentative paper?