The U.S. Energy Department explains the economic and ecological perks of its new fuel-efficiency standards.

Gratitude can do wonders for the human brain, according to researchers at UC-Berkeley, as long as it doesn't fade away when Thanksgiving ends.

Scientists say any successfully cloned animals would be used in zoos for captive breeding, and would only be released into the wild as a last resort.

The oil giant has pleaded guilty to 12 felony counts and will pay a record $4.5 billion fine. Three of its employees have also been charged with manslaughter.