Passage Summary: Giant sloths died out around the same time the ice age ended and humans showed up; scientists are shifting the blame for this extinction from the changing weather to the new human neighbors.

Conclusion: The arrival of humans shortly before the end of the last ice age was the actual cause of the giant ground sloths' extinction.

Reasoning: While scientists previously blamed climate change at the end of the ice age, they now believe human arrival is the more likely culprit for the sloths' disappearance.

Analysis: To strengthen the scientists' new belief, we need to find evidence that favors human intervention over climate change. Look for an answer that shows the sloths were resilient to climate shifts in the past or that their extinction specifically tracks with human migration patterns rather than temperature changes. If you can find a scenario where the climate changed but humans weren't there and the sloths survived, the 'human' theory becomes much more robust.