Answer the following question given this paragraph: 

Perhaps the most familiar example of corrosion is the formation of rust on iron. Iron will rust when it is exposed to oxygen and water. The main steps in the rusting of iron appear to involve the following (Figure 17.17). Once exposed to the atmosphere, iron rapidly oxidizes. anode: Fe(s) ⟶ Fe 2+(aq) + 2e −.


Q: Iron will do what when it is exposed to oxygen and water?

 Choices:

- become hot

- expand

- contract

- rust

A:
rust
