Final answer:
The claim that energy released in the post-absorptive state is only sufficient for the heart, lungs, and brain is false. The body utilizes stored energy sources such as glycogen, lipids, and proteins from various tissues to fuel all organs.
Step-by-step explanation:
The statement that the release of energy in the post-absorptive state is enough for the functioning of the heart, lungs, and brain only is false. In the post-absorptive state, energy is actually released from stores throughout the body to fuel all tissues and organs, not only the heart, lungs, and brain. The body accomplishes this by using energy sources such as stored glycogen, adipose tissue lipids, and muscle protein catabolism.
Adipose cells release stored lipids, which can be converted into glucose, ketone bodies, or ATP. Muscle cells also contribute by releasing glucose back into the bloodstream and by catabolizing amino acids to produce ATP after they undergo processes like ketogenesis and ketone oxidation in the liver.