Help Diagraming

Hi @Will, thanks for your post, but I wouldn't diagram this stimulus at all. This stimulus presents a set of facts: (1) In 1997, unusually large and intense forest fires swept the tropics (2) The tropics were quite susceptible to fire at this time, because of a widespread drought caused by an unusually strong El Nino phenomenon (3) Many scientists believe that the strength of this El Nino was enhanced by global warming, caused by air pollution These are not "sufficient" and "necessary" terms. Rather, these statements include cause & effect or correlation type reasoning. Nothing to diagram. The question stem asks you to select the answer choice that is textually supported (must be true / can be inferred) from these given facts. Answer choice (E) is correct. It says that *if* in fact air pollution enhanced the strength of the El Nino in 1997 (as "many scientists believe") then it also contributed to the widespread drought that year. This is a combination of the second and third facts presented in the stimulus. Hope this helps. Please let us know if you have any additional questions

Why is D incorrect?

@Shiyi-Zhang, Great question. Let's look at (D). (D) says, "At least some scientists believe that air pollution was responsible for the size and intensity of the forest fires that swept the tropics in 1997." From the stimulus, we know that a number of scientists think that air pollution helped to enhance El Niño. We also learned in the stimulus that an enhanced El Niño influenced the size and intensity of the large forest fires in the tropics in 1997. However, the problem is that we do not know if any scientists believed this second piece of information (that the tropics were quite susceptible to fire in 1997 because of the drought caused by a very strong El Niño). Just because part of the premise of the argument states that something is a fact does not necessarily mean that any of the scientists know this fact (or think that it's true). The only thing we know for sure that the scientists believe is is that the strength of the 1997 El Niño was enhanced by the global warming caused by air pollution. Thus, (D) is out. Hope this helps. Let us know if you have any more questions!