Question

elements, like oxygen found in the atmosphere, iron, or sulfur are made of ________ type(s) of atom.
two
three
one
many

Explanation:

An element is defined as a pure substance that consists of only one type of atom. For example, oxygen (O), iron (Fe), and sulfur (S) are all elements, meaning each is made up of only one kind of atom. So the correct option is "one".

Answer:

one (the checkbox next to "one" should be selected)