Question

which substance is a compound?
water
gold
oxygen
hydrogen

Explanation:

A compound is a substance formed when two or more elements are chemically bonded together. Water (\(H_2O\)) is made of hydrogen and oxygen elements chemically combined. Gold (\(Au\)), oxygen (\(O_2\)), and hydrogen (\(H_2\)) are elements (pure substances with only one type of atom).

Answer:

water