Because the organisms consume the departed
The principal function of thyroxine is to stimulate the consumption of oxygen and thus the metabolism of all cells and tissues.
Thyroxine is termed T4. It travels through the blood to the target cells and becomes converted to triiodothyronine or T3.
T3 is the active form of thyroxine. T3 enters the target cell's nucleus binding to genes responsible or involved in the metabolism of sugar in the body. T3 stimulates these genes and in so doing metabolism (conversion of oxygen and calories to energy) is carried out by the cell, which also results in generation of body heat.
No it does not follow a pattern
Caffeine will block the action of phosphodiesterase and thus the enzyme will not be activated to break down cAMP.
Caffeine has some effects which are psychological in nature. At the cellular level, caffeine blocks the action of phosphodiesteerase. Phosphodiesterase is the one that break down the cAMP inside the cell.