Bruce Rittmann talked about creating microbial fuel cells that use organic waste to create energy. Read more in using bacteria to make energy from waste.

Joachim von Braun of the International Food Policy Research Institute in Washington, D.C. said that biofuel policies may lead to higher food prices.

Scientists have linked car exhaust with higher risk of heart disease. That's according to a study led by research toxicologist John Incardona that started with fish.

Adventures in ecotourism: My trip to Cusco, Peru. Read about the Manu jungle and whether the ecotourism industry in Peru is really eco-friendly.

What will the future will be like? According to Ray Kurzweil, technologies are going to transform everything we do.

"If things work the same in people as in mice, and you had a perfect drug, you might imagine that you could extend life span by 20 or 30 year," said MIT biology professor Lenny Guarente. Hear more about an anti-aging gene that might extend the human life span.

A student from Laos wonders how long humans might live. An MIT biologist responds, and talks about new research that could help extend our lifespan.

“Even if we’ve made really serious progress in the fight against AIDS, the glass is half full. We still have a long way to go,” said UNAID's Peter Piot. Piot's been on the front lines of the fight against AIDS in Africa for three decades.

A new method for toxicity testing - employing robots - could one day make the need for lab animals obsolete. Read more about how robots replace animals.

Even before birth - and throughout life - all animals yawn. But scientists are still unclear about why. Robert Provine, a neuroscientist at the University of Maryland in Baltimore, has studied yawning for over 30 years. Read 'Why do we yawn?'