Set 1: Inferences (Intermediate)
Explanation
PASSAGE
Recent studies of the microbiome—the trillions of bacteria living in the human gut—suggest that these organisms influence not only digestion but also mood, immunity, and cognitive function. Scientists now refer to the gut as 'the second brain,' though the mechanisms connecting gut bacteria to mental health remain only partially understood.
Based on the passage, what can be inferred about scientific understanding of the microbiome?
Detailed Explanation
This question asks you to draw a logical conclusion from the text. The passage states mechanisms 'remain only partially understood'—correlations exist but explanations are incomplete. A valid inference must be supported by evidence in the passage, even if not stated directly. Look for clues in the text that strongly suggest the answer. Avoid conclusions that require assumptions beyond what's written. Valid inferences are strongly supported by multiple pieces of evidence in the text. Be cautious of choices that go too far beyond what the passage actually states. The best inference is the one most directly supported by textual evidence.
Key Evidence:
• "mechanisms remain only partially understood"
• "influence mood, immunity, and cognitive function"
Why others are wrong: A (It affects mood, immunity, and cognition too.), B (It's called 'the second brain'—clearly important.), C ('Partially understood' contradicts 'fully explained.').