Question

the main purpose of the section titled \environmental costs\ is to
examine the environmental impact of throwing away excess food.
argue for changes in how we dispose of excess food in landfills.
compare the impacts of wasting water to throwing away food.
advocate for better technology to help solve the problem of food waste.

Explanation:

The title "Environmental Costs" suggests a focus on the environmental - related consequences of a particular action. Throwing away excess food is an action with environmental implications, and examining this impact aligns with the title's focus. The other options involve more specific actions like arguing for landfill - disposal changes, comparing with water waste, or advocating for technology, which are not as directly related to the general idea of "environmental costs" as the first option.

Answer:

examine the environmental impact of throwing away excess food.