A peice of japanese armor was once used to protect the head of soldiers. This work has since been replaced by twenty-first century fighting gear, but the orginal armor is on display in a museum. This change over time is an example of?
1. A once-functional piece of equipment has now become a decorative item.
2. An artifact that holds physical evidence of the past.
3. Amazing technological advances in Japanese armor.
4. Deterioration of an ancient artifact.