How a terrestrial reptile will regulate body temperature if it is placed in a habitat that is extremely dry with the temperature of 55C

The temperature of terrestrial diurnal reptiles rises when the external temperature rises. However, in extreme high-temperature conditions, they need to seek a shelter with some kind of shade (for example, they hide under a rock) or they dive in the water in order to cool down

Explanation:

Terrestrial diurnal reptiles have a homeostatic regulatory mechanism known as thermoregulation, by which their body temperature may be lowered by the loss of heat (i.e., by radiation, convection and evaporation). On the other hand, these species can also raise their body temperature by heat conduction, i.e., by transferring heat from the substratum/air to the body. In consequence, when the environmental temperature is extremely high (e.g., 55°C), terrestrial diurnal reptiles need to seek a shade or some cooler spot where heat can be dissipated, i.e., where their body temperature can be lowered to normal values (27°C-35°C).