One of the advantages of Bacillus thuringiensis

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Stimulus

One of the advantages of Bacillus thuringiensis (B.t.) toxins over chemical insecticides results from their specificity for pest insects. The toxins have no known detrimental effects on mammals or birds. In addition, the limited range of activity of the toxins toward insects means that often a particular toxin will kill pest species to chemical insecticides for use as components of insect pest management programs.

What this question is testing

Weaken

Your task

Find the choice that makes the argument's conclusion less likely to be true.

Common trap

Answers that look negative but attack a claim the argument never relied on.

Winning move

Find the assumption the argument depends on, then pick the choice that undermines it.

Reading along? Open the full official question in LawHub — we show a fragment here and keep the reasoning in our own words.

The question

Which one of the following statements, if true, most weakens

Answer choices

No Impact2% picked this
Chemical insecticides cause harm to a greater number of insect species than
This statement reinforces the idea presented in the argument that chemical insecticides are more harmful broadly than B.t. toxins, which does not weaken the preference for B.t. toxins.
2%
No Impact3% picked this
No particular B.t. toxin is effective against
The statement that no particular B.t. toxin is effective against all insects aligns with the argument’s acknowledgment of the specificity of B.t. toxins. If a toxin can target certain species, we'd already assume it doesn't affect others. So this does not challenge the assertion that B.t. toxins are preferable due to their targeted effects.
3%
No Impact2% picked this
B.t. toxins do not harm weeds that do damage to
The fact that B.t. toxins do not harm weeds is irrelevant to the argument's focus, which concerns the impact on pest and non-pest insect populations. The inability to control weeds does not specifically count against B.t. toxins when focusing on insect management. If we knew that chemical pesticides not only kill insect pests but also get rid of pesky weeds, that might seem like a vote in favor of using chemical pesticides, but (A) we don't know that (B) that still wouldn't relate to Insect Management, which is all the conclusion is talking about
2%
Correct89% picked this
Insects build up resistance more readily to B.t. toxins than to
Why this is right
This is a significant drawback of using B.t. toxins, as it could undermine their long-term effectiveness in pest management. If pests develop resistance quickly, the supposed advantage of specificity could become a disadvantage, thus weakening the argument.
Skill tested: Weaken · how this choice captures the argument's function is the move to repeat next time.
89%
No Impact3% picked this
Birds and rodents often do greater damage to farm crops than
This does not directly affect the comparison between B.t. toxins and chemical insecticides since the focus is on the impact of these on insects, not other pest types.
3%

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