What does the law of conservation of energy state?

• A. Energy cannot be created or destroyed
• B. Energy is created during transformation
• C. Energy disappears as heat
• D. Energy never changes form

Answer: (A)

The main idea here is that energy cannot be created or destroyed in a closed system; it can only change form or be transferred. That means the amount of energy stays the same even as it shifts between different forms like potential, kinetic, thermal, light, or sound. The best statement describes energy as something that is not created or destroyed, but simply transformed or moved around. For example, a swinging pendulum continually converts potential energy to kinetic energy and back, and if some energy becomes heat due to friction, that heat is just another form of energy—the total amount, if you count all forms, stays constant in the system.

The other ideas don’t fit because energy isn’t created during transformation, energy doesn’t disappear as heat, and energy often changes form rather than remaining in a single form forever.