The process by which dead plants and animals decay or rot.

The movement of weathered material by wind, water and ice.

Fuels formed over millions of years from the remains of ancient plants and animals; examples include coal, petroleum (oil) and natural gas.

A picture, idea, or object that represents an object, a system, or process and is used to help with understanding; models have advantages and limitations.

The method by which a substance or object is formed.

Process by which exposed rock is broken down by rain, frost, wind, or other elements of weather.

A living thing that grows, reproduces, responds to its environment, and can function on its own.

A physical structure on Earth that occurs naturally.

Facts or other information supporting a claim or proposition.

Process by which weathered and eroded material is deposited by wind, water and ice.

Process by which overlying pressure from rocks and soil reduces the size or volume of sediments.