Economist James Hughes talks about a New Jersey ballot measure that would would offer $400 million in bonds to support land and historic preservation efforts in New Jersey. Dr. Hughes explains why land conservation is profitable for states, and becoming more so.

"We have pollution, we have massive changes to the rivers caused by dams, we alter our lakes and rivers to accommodate cities and farms," says Peter Moyle.

Serge Wich, a scientist at the Great Ape Trust of Iowa, thinks orangutan whistling could provide clues about the evolution of human speech.

Fish and snakes don't have eyelids. Some lizards have 2! Why we need eyelids ...

Within the U.S., the most pervasive problems with regards to air quality are in the area of ozone and particle pollution, says Jim Szykman.

Earth's Arctic and the Antarctic are very different kinds of places - but if these polar animals switched habitats, penguins might struggle, and polar bears might thrive.

Water is unusual in that it can occur naturally in three distinct forms - gas, liquid and solid - at the same time.

"Our water supply systems are dependent on how much water resources we've got, we don't know what the condition of our water system is," says David Maidment.

Stephan Schuster and his team compared genes from 18 different mammoths. He discovered mammoths became less genetically diverse the got closer to extinction.

Do animals laugh? If you tickle a chimp, it'll make a panting noise that sounds like a handsaw cutting wood. When dogs play, they wag their tails.