Strengthen/weaken

The stimulus assumes a causal relationship solely based on a correlation between exercise and productivity. Option B weakens this by suggesting a third variable, wealth and flexibility, which could independently cause both outcomes. Option A is incorrect because explaining how exercise biologically boosts mood would strengthen, rather than weaken, the causal claim.

The argument is strengthened by showing that a similar policy succeeded under comparable conditions elsewhere, providing empirical support for the prediction. Option A correctly identifies this analogical support. Option B is incorrect because showing successful outcomes in other states bolsters the claim rather than weakening it.

This option strengthens the causal claim by providing a control group, showing that the crime drop was unique to the city with body cameras rather than a broader regional trend. A diagram for this topic isn't available yet — the worked example below walks the same reasoning step by step.

• !Option A is incorrect because explaining how exercise biologically boosts mood would strengthen, rather than weaken, the causal claim.
• !Option B is incorrect because showing successful outcomes in other states bolsters the claim rather than weakening it.
• !Option C is incorrect because patients feeling better actually strengthens or is consistent with the claim that the vitamin worked.

Answer each from memory — you'll see instantly whether you're right and why.

Run a focused 10-question mini-mock on Strengthen/weaken and see it stick.