Logical reasoning PrepTest 117 · Section 3 · Question 15

Incorrect. It's stated as a premise/fact, so it's not a hypothesis. Also, what phytoplankton feed on wouldn't support a claim on what then feeds on phytoplankton.

Incorrect. The vertical mixing of seawater is relevant to the feeding habits of phytoplankton, not necessarily zooplankton. Also, the statement in question is part of a causal chain, not an example of another part of that chain.

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Argument Structure

Stimulus Summary:
Global warming causes a slight increase in sea temperature, which stops the vertical mixing of seawater, which restricts the availability of nutrients, which starves out phytoplankton, which feed zooplankton, which feed the rest of the food chain, inevitably resulting in there being fewer fish/seabirds.

Answer Anticipation:
This argument brings up a long causal chain to show how sea temperature increases cause declines in the fish and seabird populations. The statement in question is one of the causal links in that chain, so we should look for an answer establishing it as a premise that builds to this overall link that the argument is attempting to establish.

Answer Explanation:
This answer describes the argument and the statement in question's role within it. By bringing up a long, causal chain, the argument is showing how sea temperatures indirectly cause a change in fish/seabird populations—indirect because the warmer temperature itself doesn't directly cause those changes in population. The direct effect of that increased temperature is the prevention of the vertical mixing of seawater, and the rest are indirect. This answer is correct.

Key Takeaway:
Be sure that you stick to what's on the page when answering an Argument Structure question. Some answers will miscategorize what exactly the argument says based on what they think you'll read into it, so make sure that your understanding of the scope of the argument doesn't exceed the argument itself!

Incorrect. The argument never draws a conclusion about stopping global warming—it limits itself to discussing an effect of it.

Incorrect. The argument never states that global warming is a threat to all organisms so this answer is out of scope. That may be an implication of the argument since it does say that zooplankton feed "the rest" of the food chain but it's not an actual claim that the author goes to support.