Blaze Through 2026’s Fire Dept Customer Service Test – Ignite Your Excellence!

Understanding how a word completes a phrase to convey a natural idea about systems is key here. When a system is closed and cannot receive input from the outside world, it cannot sustain itself indefinitely; resources and energy become depleted, processes wear down, and the system eventually fails. Using the verb die makes a concise, strong statement: “Closed systems die.” It clearly communicates that the fate of a closed system is to cease functioning over time.

The other options don’t fit as well. Open would contradict the idea of a closed system and isn’t a natural completion. Expand suggests growth, which isn’t typical for a truly closed system. End is possible but weaker and less idiomatic for this context.