All animals, from the smallest to the largest, have systems, that carry out important tasks and relying on control which is based on sensing and feedback.
Plants also have a variety of systems that use sensing and feedback to control functions such as photosynthesis and respiration within the plant.
When bacteria form themselves into a plaque or biofilm, this tissue-like structure develops a form of control system, which is called quorum sensing.
Mammals and birds are called homoiothermic: they maintain their temperature by homeostasis and insulation, generating heat or cooling themselves as necessary.
Animals which do not maintain their temperature are called poikilothermic. These animals need an external source of heat such as sunlight, in order to warm up.