Passage Summary: Because it takes a lot of grain to make a little bit of meat, and we are running out of food for a growing population, the author says eating meat is about to become morally wrong.

Conclusion: Eating meat will soon become an ethically indefensible practice.

Reasoning: Meat production is highly inefficient compared to grain production, and with rising populations and shrinking farmland, we can no longer afford to waste resources on meat.

Analysis: The argument relies on the assumption that the grain used for livestock could otherwise be used to feed humans directly. To weaken this, look for an answer that suggests the resources used for meat production are not actually in competition with human food needs. For example, if the grain fed to animals is unfit for human consumption, or if the land used for grazing cannot grow crops, the 'inefficiency' argument loses its moral weight. We want to find a fact that shows meat production doesn't necessarily take food out of people's mouths.