Final answer:
Newborns lose body heat through evaporation, convection, and radiation, but not circulation. Circulation is not a direct mechanism for heat loss to the environment but rather involves the internal distribution of heat.
Step-by-step explanation:
Newborns lose body heat via evaporation, convection, and radiation, but not through circulation as a heat loss mechanism.
Heat exchange in both adults and newborns involves several mechanisms: conduction, convection, radiation, and evaporation. Conduction occurs when there is direct contact between the newborn's body and another surface, transferring heat from the warmer to the cooler object. Convection is the loss of heat as warm air or liquid moves away from the body, replaced by cooler air or liquid. Radiation refers to the loss of heat in the form of infrared rays without any physical contact. Lastly, evaporation involves the removal of heat as liquid converts to gas, such as when sweating occurs or when a wet surface on the baby's skin dries. Circulation, however, refers to the movement of blood within the body and while it does contribute to overall temperature regulation, it is not a direct mechanism by which the body loses heat to the environment.