Which principle states that energy transfer or transformation results in increased entropy and less usable energy?

• A. Second Law of Thermodynamics
• B. First Law of Thermodynamics
• C. Law of Conservation of Mass
• D. Principle of Natural Selection

Answer: (A)

The main idea is that energy transfers aren’t perfectly efficient and the usable portion of energy decreases as it moves through systems. The Second Law of Thermodynamics says that with each energy transfer or transformation, entropy increases and some energy becomes less usable, often released as heat. That’s why you see energy flowing through ecosystems in a one-way, diminishing stream: producers capture light and store some of it as chemical energy, but much is lost as heat before it reaches higher trophic levels.

This differs from the First Law, which states that energy is conserved—it's transformed but not created or destroyed—without addressing how the energy becomes less usable. The Law of Conservation of Mass is about mass balance, not energy. The Principle of Natural Selection explains evolution, not energy transformation or entropy.