The correct answer is A Turtle, snake or other reptile. This is because ectotherms are animals that rely on external sources of heat to regulate their body temperature. Reptiles, such as turtles and snakes, are ectotherms as they cannot generate their own body heat and instead rely on the environment to warm their bodies. Birds and mammals, on the other hand, are endotherms, meaning they can generate their own body heat internally.