What concern does Schlosser express regarding the environmental sustainability of fast food?

The concern expressed by Schlosser regarding the environmental sustainability of fast food focuses on the significant impact the industry has on pollution and resource depletion. Fast food production often involves intensive agricultural practices that can lead to soil degradation, excessive water use, and the use of pesticides and fertilizers that contaminate waterways. Additionally, the large-scale operations required to supply fast food chains contribute to greenhouse gas emissions and waste generation.

In contrast to the other options, the assertion that fast food has no significant environmental impact misrepresents the data, while the notions that it promotes biodiversity or that chains are leading in sustainability practices overlook the industry's prevalent reliance on monocultures and other practices that prioritize efficiency and profit over ecological balance. Hence, Schlosser's emphasis on these adverse effects draws attention to a crucial aspect of the fast-food industry's operations that requires consideration and action towards true sustainability.