Final answer:
An inert missile is safe for display in public areas because it has been rendered non-functional by removing its explosive and moving parts.
Step-by-step explanation:
The inert missile on display in the science museum has had all dangerous components removed. An inert missile is one that has been rendered non-functional by removing or deactivating its explosive and propulsive elements, making it safe for public display. This is in contrast to an active missile, which is fully operational; a nuclear missile, which is armed with a nuclear warhead; or an experimental missile, which is used for testing new technologies or systems.