The authors' primary purpose in the passage is to

Jasmin on July 15, 2021

Why is A wrong?

I know another discussion asked this question but it wasn't answered and I would like to know why D is correct and not A. I had a similar thought process to the other person who asked which said "It seemed to me that the author was discussing a topic that’s seemed to confuse the scientific community because of evolutionary data and the timeline in question. I understand that there is hypothesis in this but I don’t see how the author is truly proposing it at the whole time the author seemed to be discussing the hypothesis in question?"

Replies

Steven on July 17, 2021

Why is A wrong? Can we get an answer to this?

Ross on January 10, 2022

On "primary purpose" questions in RC, we're concerned with *why* and *how* the passage was written. The correct answer will describe an action: what the author hoped to do in the passage, and how the author accomplished that.

Now, in a broad sense, every author hopes to convince us that the main point is true. However, different authors employ different means to convince us of that main point.

In this passage, "propose a hypothesis" is the best description of what the author hoped to do in the passage. Notice how the main point is conveyed: "The implication is that the adoption of cooked food created opportunities for humans to use diets of high caloric density more efficiently. Selection for such efficiency, we suggest, led to an inability to survive on raw-food diets in the wild." The "we suggest" part, especially, indicates that the author wants to pose an explanation, or hypothesis, for why most humans can no longer eat only raw foods. Additionally, later in the passage, the author addresses important questions that need to be tested before we can accept the author's explanation. (We need more data on tooth size/cooking adoption, and we need to figure out whether evolutionary changes in our guts can be explained by cooking, rather than a raw-meat diet.) Because these questions have not been answered, it's best to consider the passage a "proposing a hypothesis" rather than a more definitive description like "explaining a phenomenon."

For (A), "describe a scientific puzzle" is not a very fitting description. Although our inability to subsist on raw foods alone could be labeled a "scientific puzzle," "describe" is a neutral word. The correct answer to a primary purpose question would use a neutral word like "describe" only if the author did not have their own argument they wanted to advance. On such a passage, the author would present someone else's argument, without any indication whether the author endorsed that argument. Clearly, this author has their own argument about cooking and anatomical changes that they want to advance. Moreover, most of the passage is about questions the author wants to study. "Describe" does not accurately convey what the author is hoping to accomplish there either.