Logical reasoning PrepTest 114 · Section 4 · Question 3

Incorrect. First, there's no statement that photosynthesis is necessary for animal life. Second, there's no indication that animal life is necessary for it in plants—while carbon dioxide would be depleted without animals, there's no indication in the stimulus that that would end photosynthesis (remember—don't bring outside information to the stimulus!). Also, parts of the stimulus that mention these concepts aren't supported by others, so they're at best premises.

Incorrect. The argument states that no animals would survive without plants, so this answer about purely carnivorous animals is too limited in scope to even match with that opening statement. Additionally, the Journalist pivots away from that statement, which means it isn't the main point.

Incorrect. This answer is an implication of some of the premises of the argument, but it's not stated, and it's not what the argument is building towards, so it's not the main point.

Incorrect. The stimulus discusses only carbon dioxide, not oxygen, so this answer is out of scope.

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Main Point

Stimulus Summary:
Animals need plants, but plants also need animals, because animals do a bunch of things that plants rely on to survive.

Answer Anticipation:
The argument here starts with a discussion about animals' dependence on plants, but it then pivots ("But") to a discussion about the dependence it just noted (animals depending on plants) being mutual. When an argument pivots away from one topic to another, we're moving from some type of opposing point or separate topic to the main topic of the argument, and when the pivot statement highlights an opinion or judgment, it's almost certainly the main point of the argument.

Here, the pivot statement (once we substitute in the concepts it refers back to) says that plants depend on animals for survival. That skirts the line between a fact and a judgment/opinion, so we need to read on to see if it's supported.

The following statements all highlight ways in which plants depend on animals for their survival. As such, the pivot statement receives proof throughout the rest of the stimulus, and it's therefore the main point of the Journalist's argument. Let's find an answer stating that the main point of the argument is that plants depend on animals for survival.

Answer Explanation:
This answer brings up the dependence of plants on animals, which was the pivot statement that the Journalist backed up with a few ways on which plants depend on animals. It also reflects the initial point which was a similar judgment that the Journalist believes to be true but that she pivoted away from. Since the first half of this answer is a judgment the author agrees with and the focus is on the second half of the answer ("Just as . . . plants are . . . "), this answer reflects the main point.

Key Takeaway:
Rely on structural indicator words to help you through Main Point questions! Especially early on, they can completely determine the argument's structure and let you identify the main point in short order.