Final answer:
A reptile's body temperature will decrease with a 20-degree Celsius drop in outside temperature due to their ectothermic nature. They become sluggish and may enter estivation to conserve energy, performing only vital functions to survive.
Step-by-step explanation:
If the outside temperature decreases by 20 degrees Celsius, a reptile's body temperature will also decrease. This is because reptiles are ectothermic organisms, meaning their internal body temperature is determined by their surrounding environment. Unlike endothermic animals, which can generate internal heat to maintain constant body temperature, reptiles must rely on behavioral adaptations to regulate their temperature. Reptiles, such as an American alligator basking in the sun, absorb heat when it is available to increase their body temperature.
When environmental temperatures drop, reptiles like snakes will seek shelter and become sluggish as their body temperature falls. This slowdown can affect their heart rate, breathing rate, and overall metabolic function. Some reptiles may enter a state of estivation, a period of inactivity and lowered metabolic rate, to conserve energy and survive until temperatures become favorable again. In essence, a reptile's body will perform only critical activities necessary to sustain its living state during such times.