It occurs without an overall input of energy.Group of answer choicesmetabolismenergy couplingspontaneous processendergonic reactionNext

To address the question about processes that occur without an overall input of energy, let's analyze the given options:

1. Metabolism: This is a broad term that includes all the chemical reactions that occur within a living organism to maintain life. Metabolic processes can be both energy-consuming (anabolic) and energy-releasing (catabolic).

2. Energy Coupling: This refers to the use of energy released from one reaction to drive another reaction. It typically involves coupling an exergonic reaction (which releases energy) to endergonic reactions (which require energy).

3. Spontaneous Process: A spontaneous process is one that occurs naturally and without the need for continuous external energy input. While spontaneous processes often release energy, they do not require energy input to occur.

4. Endergonic Reaction: This type of reaction requires an input of energy to proceed, meaning it is not spontaneous and does not occur naturally without outside energy.

Conclusion:

The correct answer is spontaneous process, as it refers to a process that can occur without an overall input of energy. Spontaneous processes can happen naturally in certain conditions and are typically favored in thermodynamic systems.