The production of heat (fever) is controlled in the hypothalamus and ________________.

The production of heat, or fever, is indeed primarily controlled by the hypothalamus, which acts as the body’s thermostat. The brain stem plays a supportive role in this process by regulating various autonomic functions and responses that can influence temperature control. Specifically, the brain stem is involved in the autonomic pathways that can facilitate mechanisms like shivering or sweating, which help the body to either generate heat or dissipate it in response to hypothalamic signals.

The other choices do not play a direct role in the production or regulation of heat. The heart does not directly influence body temperature control—it primarily pumps blood and supports circulation. The epidermis contributes minimally to temperature regulation, mainly through processes like sweat evaporation, but does not play an active role in generating heat. Lastly, the liver is involved in metabolic processes that can generate heat through energy production, but it does not control the actual temperature regulation process like the hypothalamus and brain stem do. Thus, the brain stem is integral to the overall response to changes in body temperature initiated by the hypothalamus.