Question 9·Hard·Command of Evidence
Number and Origin of Clamshell Tools Found at Different Levels Below the Surface in Neanderthal Cave
| Depth of tools found below surface in cave (meters) | Tools made from clamshells that Neanderthals collected from the beach | Tools made from clamshells that Neanderthals harvested from the seafloor |
|---|---|---|
| 3–4 | 99 | 33 |
| 6–7 | 1 | 0 |
| 4–5 | 2 | 0 |
| 2–3 | 7 | 0 |
| 5–6 | 18 | 7 |
Studying tools unearthed at a cave site on the western coast of Italy, archaeologist Paola Villa and colleagues have determined that prehistoric Neanderthal groups fashioned them from shells of clams that they harvested from the seafloor while wading or diving or that washed up on the beach. Clamshells become thin and eroded as they wash up on the beach, while those on the seafloor are smooth and sturdy, so the research team suspects that Neanderthals prized the tools made with seafloor shells. However, the team also concluded that those tools were likely more challenging to obtain, noting that ______
Which choice most effectively uses data from the table to support the research team’s conclusion?
For command-of-evidence questions with a table, first restate the exact claim in the sentence containing the blank (here: seafloor shells were harder to obtain). Then scan the table for the most direct recurring pattern that bears on that claim (here: beach-shell tools outnumber seafloor-shell tools at every depth). Choose the option that states that pattern accurately and ties it logically to the claim, and eliminate options that pivot to different conclusions (timing, overall activity, preference) even if they cite numbers.
Hints
Restate the claim you must support
The blank must support this specific idea: seafloor shells were more challenging to obtain than beach shells.
Find the simplest repeating comparison
Compare the beach-tool count to the seafloor-tool count in each row. Is one column consistently larger?
Eliminate choices that shift the conclusion
Be wary of choices that switch the conclusion to something else (like when harvesting happened, overall toolmaking activity, or preference for a material) instead of difficulty of obtaining seafloor shells.
Step-by-step Explanation
Identify the exact conclusion to support
The blank must support the team’s claim that tools made from seafloor shells were more challenging to obtain.
So the best choice should use the table to show seafloor shells were obtained less often than beach shells.
Compare beach vs. seafloor counts at each depth
Read across each row and compare the two right-hand columns:
- 2–3 m: 7 beach vs. 0 seafloor
- 3–4 m: 99 beach vs. 33 seafloor
- 4–5 m: 2 beach vs. 0 seafloor
- 5–6 m: 18 beach vs. 7 seafloor
- 6–7 m: 1 beach vs. 0 seafloor
At every depth, the number of beach-shell tools is greater than the number of seafloor-shell tools.
Link the pattern to difficulty of obtaining shells
If seafloor shells were harder to obtain, fewer tools made from those shells would be expected across the layers.
A consistent pattern of fewer seafloor-shell tools than beach-shell tools supports the conclusion that seafloor shells were more challenging to obtain.
Select the choice that states that support directly
The option that explicitly connects the consistent difference (more beach-shell tools at each depth) to ease of collection is:
at each depth below the surface in the cave, the difference in the numbers of tools of each type suggests that shells were easier to collect from the beach than to harvest from the seafloor.