Passage Summary: Because low oxygen made climbers bad at both talking and thinking at the same time, the author thinks the brain doesn't have separate areas for those tasks.

Conclusion: The theory that the brain's speech center is separate from the centers controlling other functions is incorrect.

Reasoning: In a study of mountain climbers, oxygen deprivation at high altitudes caused simultaneous impairment in speech, sentence comprehension, and judgment.

Analysis: The author is making a huge leap by assuming that because one cause (low oxygen) affected multiple functions, those functions must be handled by the same part of the brain. This is a classic 'common cause' error. Think of it like a power outage in a house: just because the lights and the refrigerator both stop working doesn't mean they are the same appliance. Look for an answer that points out that a single systemic factor can independently affect multiple distinct systems or regions at once.