Which of the following correctly identifies a characteristic of ectotherms?

Ectotherms are organisms that rely heavily on external environmental conditions to regulate their body temperature. This characteristic distinguishes them from endotherms, which can internally regulate their body temperature through metabolic processes. Ectotherms, such as reptiles and amphibians, often bask in the sun to increase their body temperature or seek shade to cool down. This reliance on environmental sources of heat and cold makes them highly adaptable to their surroundings but limits their activity in extreme temperatures.

The other options present characteristics that are typical of endothermic organisms instead of ectothermic ones. Therefore, this choice accurately reflects the nature of ectothermic physiology in managing body temperature.