What are fat bodies in frogs primarily used for?

Fat bodies in frogs serve primarily as an energy reserve and for buoyancy. These structures are composed of adipose tissue, which stores lipids that can be metabolized for energy when food is scarce, particularly during hibernation or periods of dormancy. This energy reserve is crucial as it allows frogs to survive when environmental conditions are not favorable.

Moreover, fat bodies also contribute to the buoyancy of frogs in aquatic environments. The lipid content in these structures is less dense than water, which helps in maintaining the frog's buoyancy as it swims or rests in water. This dual role of serving as both an energy reserve and aiding in buoyancy is vital for the frog's survival and overall fitness in its habitat.

Other options, while relevant to various biological functions, do not encompass the main purposes of fat bodies in frogs as effectively as the correct choice does.