LSAT Explanation PT 38, S4, Q3: Journalist: Obviously, though some animals are
LSAT Question Stem
Which one of the following most accurately expresses the main conclusion of the journalist's argument?
Logical Reasoning Question Type
This is a Main Conclusion question.
Correct Answer
The correct answer to this question is E.
LSAT Question Complete Explanation
First, let's analyze the argument in the passage. The journalist is discussing the mutual dependence between animals and plants. The argument can be broken down into the following parts:
1. Premise: Some animals are purely carnivorous, but none would survive without plants.
2. Premise: Many plant species need animals to pollinate, fertilize, and broadcast their seeds.
3. Premise: Plants' photosynthetic activity would deplete the carbon dioxide in Earth's atmosphere if it weren't for the exhalation of animals, engine fumes, and smoke from fires, many set by human beings.
4. Conclusion: Just as animals are dependent on plants for their survival, plants are dependent on animals for theirs.
The question type of this problem is Main Conclusion, which asks us to identify the main conclusion of the journalist's argument. Now, let's discuss each answer choice:
a) The photosynthetic activity of plants is necessary for animal life, but animal life is also necessary for the occurrence of photosynthesis in plants.
- This answer choice is not correct because it focuses on the necessity of photosynthesis for both plants and animals, but it doesn't capture the overall mutual dependence between plants and animals that the journalist is arguing.
b) Some purely carnivorous animals would not survive without plants.
- This answer choice is incorrect because it only addresses a specific premise (the first premise) and does not capture the main conclusion of the argument, which is about the mutual dependence between plants and animals.
c) The chemical composition of Earth and its atmosphere depends, at least to some extent, on the existence and activities of the animals that populate Earth.
- This answer choice is incorrect because it only focuses on the relationship between animals and Earth's atmosphere, while the main conclusion of the argument is about the mutual dependence between plants and animals.
d) Human activity is part of what prevents plants from depleting the oxygen in Earth's atmosphere on which plants and animals alike depend.
- This answer choice is incorrect because it only addresses a specific premise (the third premise) and does not capture the main conclusion of the argument, which is about the mutual dependence between plants and animals.
e) Just as animals are dependent on plants for their survival, plants are dependent on animals for theirs.
- This is the correct answer because it accurately captures the main conclusion of the journalist's argument, which is that plants and animals have a mutual dependence on each other for survival.
In conclusion, the correct answer is E, which accurately expresses the main conclusion of the journalist's argument: Just as animals are dependent on plants for their survival, plants are dependent on animals for theirs.