Energy for the cell's use is stored when?

A. ADP and P form ATP

B. Acetic acid is formed

C. Glucose is broken into pyruvic acid

D. CO2 is released from the reaction

A. ADP and P form ATP. GOOD LUCK!

A

Explanation:

ADP and P (an inorganic phosphate) combining to form ATP, is a non spontaneous reaction, and therefore requires energy. ATP can be used as a universal energy source, and contains high energy bonds within the molecule that, when broken down, release energy.

The other options are all examples of situations that occur when energy is released, as opposed to storing energy as the question asks.

Acetic acid is a by-product of fermentation (which occurs when oxygen is not available).

The break down of glucose releases energy.

CO₂ is released as a by-product of respiration (the break down of glucose)