Many cows are fed a high-protein diet, which creates a more liquid manure that is easier to spray on fields.

Atrazine - a herbicide often used on corn fields, golf courses and even lawns - has become one of the most common contaminants in American drinking water.

One goal of the Clean Water Act of 1972 was to upgrade the nation's sewer systems, many of them built more than a century ago, to handle growing populations and increasing runoff of rainwater and waste.

Economists at the National Bureau of Economic Research and University of Chicago persuasively argue that one of the biggest reasons for the nation's current obesity epidemic is that food is now so much cheaper and easier to prepare.

There are supply chains that exist in China and Asia now which the U.S. simply can't replicate.

In surveys, many borrowers say reverse mortgages have improved their lives and provided money they needed for retirement.