Here's why:

* Active: An active volcano is one that has erupted in recent history and is likely to erupt again.

* Dormant: A dormant volcano is one that has not erupted recently but is still considered potentially active.

* Extinct: An extinct volcano is one that is unlikely to erupt again.

The type of volcano (shield, composite, etc.) does not determine its activity level. A shield volcano's shape is determined by its eruptive style, which involves effusive eruptions of fluid lava.

Examples:

* Active shield volcano: Mauna Loa in Hawaii

* Dormant shield volcano: Fernandina in the Galapagos Islands

* Extinct shield volcano: Kohala on the Big Island of Hawaii

Therefore, a shield volcano can be active, dormant, or extinct.