In a closed system, which statement about energy is true?

• A. Energy vanishes in closed systems
• B. Energy cannot be created or destroyed, only transformed
• C. Energy can be created in closed systems
• D. Energy cannot be transferred in closed systems

Answer: (B)

Energy is conserved in a closed system: the total amount stays the same even as it changes form or moves across the system’s boundaries. Energy can transfer as heat or work, and it can switch between forms like kinetic, potential, or chemical energy, but it isn’t created or destroyed. That’s why the statement that energy cannot be created or destroyed, only transformed, is true for a closed system. The other ideas would imply energy disappears or cannot move, which isn’t consistent with how closed systems are defined.