Question

definition: a pure substance that cannot be broken down into simpler substances by physical or chemical means. sentence: oxygen is just one element that makes up a water molecule. choose the best answers. many elements occur naturally on earth. which substances are examples of these pure substances? a copper b gold c helium d water

Explanation:

Elements are pure substances that cannot be broken down into simpler substances by physical or chemical means. Copper, gold, and helium are elements. Water is a compound made up of hydrogen and oxygen.

Answer:

A. copper
B. gold
C. helium