A finding question that asks you to challenge an interpretation tests whether new evidence weakens the researchers’ explanation. Put the claim in a few words, and name the cause they favor and the one they reject. Then ask what the study kept the same and what it left open. A finding weakens a claim if it weakens the link between cause and result or gives evidence for another cause. Findings that share the topic may still leave the claim untouched.
Hints
- Hint 1
Find the two possible causes named in the interpretation. Which one do the researchers favor?
- Hint 2
Look at when the egg capsules were collected and how the hatchlings were raised. Ask what those conditions can tell you about the two possible causes.
Step-by-step
Separate genes from parental effects
Step 1Identify the disputed cause
Hatchlings from mothers on crab-rich shores grew thicker shells under identical, cue-free laboratory conditions. What do the researchers think caused that gap? They favor inherited genetic differences between the populations over effects of parental environments carried into offspring, so a challenge must weaken their explanation of the gap’s cause.
- Step 2
Find what the lab left open
What did those lab conditions rule out? They removed crab-cue exposure after hatching, but the researchers collected unhatched egg capsules from crab-rich and crab-poor shores. Effects already passed from mothers into eggs could still shape shell growth, even when the hatchlings share the same surroundings. To challenge the claim, we’d look for evidence that the gap reflects parental effects rather than mainly genes.
- Step 3
Set aside findings that don’t challenge the cause
Does each finding challenge the cause of this persistent difference? The finding about variants associated with shell formation favors genes, while the same proportion of thickening after crab cues concerns how snails react to cues they didn't encounter in the lab. Survive crab attacks more often tells us why thicker shells help, not why the hatchlings grew them. None weakens the claim about the lab gap’s cause.
- Step 4
Use later generations to test the interpretation
What does the two generations finding show about inherited genetic differences between the populations? Breeding the snails separately by origin keeps the populations from mixing, yet the shell gap disappears under the same cue-free conditions. First-generation thickness also tracks nutrient levels in the original egg capsules, linking the early gap to what mothers put into their eggs. That pattern favors parental effects that fade across generations, challenging genes as the main cause. Choice D.