Self-study
In ancient Mesopotamia, prior to 2900 B.C., wheat was cultivated in considerable quantities, but after 2900 B.C. production of that grain began to decline as the production of barley increased sharply. ████ ██████████ ███ █████ ███████ ███████████ ███████ ████ ███ ███████ ██ █████ ██████████ ███ ███ ██ █████████ ███████████ ████ ██ █████████ ███ ███ ██████████ ████████████ ██ ████ ████████ ██ ███ █████
Summarize Argument: Phenomenon-Hypothesis
Historians hypothesize that the decline in Mesopotamian wheat production was ulimately caused by a buildup of salt in soil, caused by too much irrigation and lack of drainage. We aren't given the historians' evidence for this hypothesis.
Notable Assumptions
The historians assume that there is a negative connection between wheat production and salt buildup in the soil, while barley is perhaps unaffected by, or might even benefit from, soil with more salt accumulation.
25.
Which one of the following, ██ █████ ████ █████ ██ ███████ ███ ███████████ ██████████ ██████████ ███ ███████ ███ ███ ███████ ██ █████ ██████████ ██ ███████ ████████████
a
The cultivation of ██████ ████████ ████████████ ████ █████ ████ ████ ███ ███████████ ██ ██████
This points out a separate advantage of barley compared to wheat, but it doesn't strengthen the specific hypothesis that the buildup of salt residues in the soil drove the shift from wheat to barley. Even if barley required less irrigation, and so led to less salt buildup in the future, this wouldn't get rid of the salt residues already in the soil from the excessive irrigation for wheat. We still want to know how that initial salt buildup related to the shift from wheat to barley.
Directionally wrong
Directionally wrong
Answers that, if they have any effect, do the opposite of what we want (weaken when we're trying to strengthen, or strengthen when we're trying to weaken).
b
Barley has much ███████ ██████████ ██ ███ ████████ ██ ████ ██ ████ ████ ████ ██████
This supports the idea that salt buildup drove the shift away from wheat and towards barley. Wheat struggled in soil with salt buildup, while barley was able to handle those conditions better.
Plausibility
Plausibility
Presenting evidence that corroborates (in Strengthen) or conflicts (in Weaken) with the author's hypothesized explanation or the predictions that follow from that explanation.
c
Prior to 2900 █████ ██████ ███ ██████████ █████ ████ ██████ ███ ███ ██████ ██ ██████ ████████ ███ ███ ████ ████ ███ ██████ ██ █████ █████████
This just describes the proportion of wheat to barley before 2900 B.C. It doesn't explain why there was a shift after 2900 B.C., or support the historians' explanation for that shift.
d
Around 2900 B.C., █ ██████ ██ █████ ███████ █████████ ██████████ ████ ██ ███ █████ ████ ████ █████ █████
This actually weakens the author’s argument, because it provides a different reason -- the wheat blights -- for why wheat production decreased and there was a shift to producing barley.
Directionally wrong
Directionally wrong
Answers that, if they have any effect, do the opposite of what we want (weaken when we're trying to strengthen, or strengthen when we're trying to weaken).
e
Literary and archaeological ████████ █████████ ████ ██ ███ ██████ █████████ ████ █████ ██████ ██████ ███ █████████ █████ ██ ███ ████ ██ ████ ██ ███ ███████████ ██ ████████████
This just gives further support for something we already know: that barley began to be produced much more after 2900 B.C. But this answer choice doesn't support the historians' hypothesis, because it doesn't tell us anything about what caused the change.