The correct statement is option 'A': Energy produced during respiration is stored in the form of ATP in animals.

Respiration and ATP:
Respiration is the process by which living organisms obtain energy from the food they consume. It involves the breakdown of glucose and other organic molecules in the presence of oxygen, resulting in the release of energy. This energy is then used to perform various cellular functions.

ATP, or adenosine triphosphate, is the primary molecule used by cells to store and transfer energy. It is often referred to as the "energy currency" of the cell. ATP consists of an adenosine molecule and three phosphate groups. When one of the phosphate groups is cleaved off from ATP, it releases a significant amount of energy that can be used by the cell.

Energy Storage in ATP:
During the process of respiration, glucose is broken down through a series of biochemical reactions, such as glycolysis, the Krebs cycle, and oxidative phosphorylation. These reactions result in the production of ATP.

The energy released during the breakdown of glucose is used to add a phosphate group to adenosine diphosphate (ADP), forming ATP. This process is called phosphorylation. The phosphate group is attached to the ADP molecule through a high-energy bond.

ATP stores the energy in this phosphate bond, and when required, it can be easily broken to release the stored energy. The energy released is used by the cell to perform various functions like muscle contraction, active transport, synthesis of macromolecules, and many other cellular activities.

Comparison between ATP and ADP:
ADP, or adenosine diphosphate, is an intermediate molecule that is formed when ATP loses one of its phosphate groups. ADP has lower energy content compared to ATP because it lacks one of the high-energy phosphate bonds.

During cellular respiration, when energy is required, ADP can be quickly converted back to ATP by adding a phosphate group through the process of phosphorylation. This replenishes the ATP stores and allows the cell to continue utilizing energy for its metabolic activities.

Conclusion:
In conclusion, the correct statement is that energy produced during respiration is stored in the form of ATP in animals. ATP acts as a carrier and storage molecule for energy, allowing cells to quickly access and utilize the energy generated during the breakdown of glucose. ADP, on the other hand, has lower energy content and can be easily converted back to ATP when energy is needed.