LSAT Explanation PT 35, S4, Q5: One of the advantages of Bacillus

LSAT Question Stem

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

Logical Reasoning Question Type

This is a Weaken question. 

Correct Answer

The correct answer to this question is D. 

LSAT Question Complete Explanation

Let's first analyze the argument in the passage. The conclusion of the argument is that B.t. toxins are preferable to chemical insecticides for use as components of insect pest management programs. The premises supporting this conclusion are: 1) B.t. toxins are specific to pest insects and have no known detrimental effects on mammals or birds, and 2) the limited range of activity of the toxins toward insects means that often a particular toxin will kill pest species but not affect insects that prey upon the species.

To make this more understandable, let's use a simple example. Imagine there are two types of products to eliminate pests in your garden: Product A (B.t. toxins) and Product B (chemical insecticides). Product A only targets the harmful pests and doesn't harm other insects, animals, or plants. Product B, on the other hand, may harm other insects, animals, and plants while eliminating the pests. The argument is saying that Product A (B.t. toxins) is preferable to use in pest management programs because of its specificity.

Now, the question type is Weaken, and we need to find the answer choice that most weakens the argument.

a) This answer choice actually strengthens the argument by emphasizing the specificity of B.t. toxins compared to chemical insecticides. It doesn't weaken the argument.

b) The fact that no particular B.t. toxin is effective against all insects doesn't weaken the argument, as it doesn't need to be effective against all insects to be preferable for pest management programs.

c) B.t. toxins not harming weeds that damage farm crops is irrelevant to the argument, as the focus is on insect pest management programs, not weed control.

d) This is the correct answer. If insects build up resistance more readily to B.t. toxins than to chemical insecticides, it weakens the argument that B.t. toxins are preferable for use in pest management programs. This answer choice introduces a disadvantage of B.t. toxins compared to chemical insecticides, making them potentially less effective in the long run.

e) The fact that birds and rodents often do greater damage to farm crops than insects is irrelevant to the argument, as it doesn't address the comparison between B.t. toxins and chemical insecticides for insect pest management programs.

An "Evaluate" question for this argument could be: "Do insects develop resistance to B.t. toxins and chemical insecticides at similar rates?" The answer to this question would help determine the validity of the argument, as it would reveal whether B.t. toxins maintain their advantage over chemical insecticides over time.