1. Reptiles and amphibians are ectotherms, meaning they rely on external heat sources to regulate their body temperature.
爬行动物和两栖动物都属于冷血动物，也就是说它们依靠外部热源来调节体温。
2. Ectotherms are able to conserve energy by slowing down their metabolic rate in colder environments.
冷血动物可以通过在寒冷环境中降低新陈代谢速率来节约能量。