Logical reasoning PrepTest 140 · Section 2 · Question 24

Incorrect. The argument supports the statement in question by establishing the complexity of the bacteria, lending credence to the idea that it must have already had a long evolutionary history.

Incorrect. As explained in answer choice (A), the argument supports the statement in question by establishing the complexity of the bacteria, lending credence to the idea that it must have already had a long evolutionary history.

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Argument Structure

Stimulus Summary:
Bacteria discovered in 3.5b year old rocks were complex, so they must have been around for a while. Earth is only 1.1b years older, so this life must have developed soon after, in harsh conditions, and thus life must be able to form in many difficult conditions.

Answer Anticipation:
Wow, that's a lot of conclusions! The argument starts with a discovery, which is almost certainly a premise since it's a fact. The implication is likewise a fact—there's no support that the fossils are quite complex other than that it's asserted. This complexity, however, is used to support that it "must have" (conclusion language, since it suggests an inference and not a fact) already had a long evolutionary history ("and so . . . "), which is the statement in question. So the statement in question is a conclusion of some type.

From there, the argument adds more facts—Earth is 4.6b years old—as premises. Combined with the statement in question, this fact supports the conclusion ("so . . . must have") that the first life on Earth must have appeared shortly after it formed—after all, it already had a long history 1.1b years later. So the statement in question is an intermediate conclusion.

But the argument isn't done! All of "[t]his suggests" (conclusion indicator language) that life can form in difficult conditions, the main point of the argument. So the statement in question is a conclusion supporting a conclusion that then goes on to support yet another conclusion!

Answer Explanation:
This answer describes the argument and the role of the statement in question correctly. It's a conclusion that supports a conclusion that supports the main point. Convoluted? Yes, but also correct!

Key Takeaway:
This argument just kept piling on the conclusions! However, unlike other arguments with intermediate conclusions, the structure here kept building off of prior statements, so there was no need to see which supported the others—the structure itself told us that each conclusion built on the previous one.

Incorrect. The statement in question does receive some support, but it also goes on to support the other conclusions. The long evolutionary history of the bacteria supports that it formed shortly after Earth did, which in turn supports that life can arise in harsh conditions such as those on early Earth.

Incorrect. This answer gets the three conclusions right, but it doesn't connect the second conclusion as an intermediate conclusion to the third. The conclusion that life formed on early Earth where conditions were harsh supports the conclusion that life can arise in many such environments.