Passage Summary: Ancient people had much better teeth than we do, so they probably ate very different food.

Conclusion: The dietary habits of prehistoric humans were likely significantly different from those of people today.

Reasoning: Ancient skeletal remains demonstrate that our ancestors suffered from far fewer dental issues than modern populations do.

Analysis: The argument relies on a causal assumption that the difference in dental health is primarily due to diet rather than other factors like genetics or modern hygiene. To strengthen this claim, we should look for an answer that reinforces the link between specific modern dietary staples and the dental problems ancestors lacked. If we find evidence that modern foods like refined sugars are the sole cause of these issues, the conclusion becomes much more plausible.