Passage Summary: Scientists believe that as Earth's orbit wobbles, it occasionally drifts through thick clouds of space dust that block out the sun, causing the planet to freeze over.

Conclusion: The Earth's recurring ice ages are triggered by the planet's passage through dense cosmic dust clouds during specific orbital fluctuations.

Reasoning: Orbital cycles align with ice age timing, and cosmic dust is known to dim solar radiation, though the dust must be significantly dense to cause cooling.

Analysis: Since this is a 'Strengthen EXCEPT' question, we are looking for the one answer choice that does not provide additional evidence for the dust-ice age link. To support the climatologists, an answer might provide physical evidence of dust in ice cores or explain why the orbital fluctuations specifically lead to dust encounters. The incorrect options will likely bridge the gap between the 'fluctuations' and the 'dense dust' requirement. Look for an answer that is either irrelevant to the mechanism or perhaps even suggests a different cause for the cooling.