A living thing.

A type of organism made up of only one cell.

A type of organism made up of many cells.

The mistaken idea that living things arise from nonliving sources.

The basic unit of structure and function in living things.

A widely accepted explanation of the relationship between cells and living things.

A tiny cell structure that carries out a specific function within the cell.

Any substance that cannot be broken down into simpler substances.

The smallest unit of an element.

Two or more elements that are chemically combined.

The smallest unit of most compounds.

Energy-rich organic compounds, such as sugars and starches, that are made of the elements carbon, hydrogen and oxygen.

Large organic molecules made of carbon, hydrogen, oxygen, nitrogen, and sometimes sulfur.

Small molecules that are linked together chemically to form proteins.

A type of protein that speeds up a chemical reaction in a living thing.

Energy-rich organic compounds, such as fats, oils, and waxes, that are made of carbon, hydrogen, and oxygen.