William finds a piece of pure iron in his garden. After a few days, the iron begins to rust. What are the two types of substances involved in the rusting process of iron?

Iron is ... With one kind of atom that combines with oxygen from the air to form rust (iron oxide)., Rust contains two types of atoms, which means it is ...

1)

-a compound

- an element

- a mixture

2)

-a compound

-an element

-a mixture