The Mayan languages form a language family spoken in Mesoamerica and northern Central America. Mayan languages are spoken by at least 6 million indigenous Maya, primarily in Guatemala, Mexico, Belize and Honduras. In 1996, Guatemala formally recognized 21 Mayan languages by name, and Mexico recognizes eight more. The Mayan language family is one of the best documented and most studied in the Americas. Modern Mayan languages descend from Proto-Mayan, a language thought to have been spoken at least 5,000 years ago.

Plasma is one of the four fundamental states of matter (the others being solid, liquid, and gas). Heating a gas may ionize its molecules or atoms (reducing or increasing the number of electrons in them), thus turning it into a plasma, which contains charged particles: positive ions and negative electrons or ions.

The expert predicted that America's gross domestic product will return to more than 3 percent yearly expansion. For example, Dow Chemical is investing $4 billion in Texas plastics production that will be operational by 2019. Such growth requires cheap oil and natural gas - and "by 2022 or so, the United States will surpass Saudi Arabia in oil output, and Russia in gas." He continued: "The big attraction is the low price of natural gas, the lowest-carbon fossil fuel, which can be produced profitably at about a third the price per unit of energy as other hydrocarbons. That is particularly attractive to chemical companies. It is the raw material for plastics, Styrofoam, tires, sealants, adhesives, films, liquid crystal screens, nylons, polyesters - nearly everything around us."

A perennial stream or perennial river is a stream or river (channel) that has continuous flow in parts of its stream bed all year round during years of normal rainfall. "Perennial" streams are contrasted with "intermittent" streams which normally cease flowing for weeks or months each year, and with "ephemeral" channels that flow only for hours or days following rainfall.

The South Shore Estuary is an estuary located along the south shore of Long Island, between the mainland and the outer barrier islands, in eastern New York state. It stretches for over 70 miles (110 km) from West Bay in Nassau County to the Shinnecock Bay in Suffolk County.