What physiological term can he used to describe the regulation of the body temperature of the lizard? '

The physiological term that can be used to describe the regulation of the body temperature of a lizard is "poikilothermy". Poikilothermy refers to the characteristic of an organism whose body temperature varies with that of the external environment. Lizards, along with other cold-blooded animals such as snakes and turtles, are poikilothermic. Lizards are not able to regulate their body temperature internally like warm-blooded animals, such as mammals and birds. Instead, they rely on external sources of heat, such as basking in the sun or resting on warm surfaces, to raise their body temperature. Conversely, they may seek out shade or cooler areas to lower their body temperature. This reliance on external sources of heat means that the body temperature of a lizard can vary greatly depending on the temperature of its environment. However, lizards are able to maintain a degree of stability in their internal processes through other mechanisms such as behavioral adjustments and physiological changes. In summary, the regulation of body temperature in lizards is an example of poikilothermy, where the organism's body temperature varies with that of the external environment.