Ectotherms, such as reptiles and amphibians, rely on external environmental temperatures to regulate their body temperature, making them less capable of controlling their body temperature compared to endotherms (warm-blooded animals).
Among the options provided, animals with a low surface area to volume ratio are generally better at retaining heat due to reduced heat loss, which can aid in temperature regulation. Therefore, the best answer concerning animals that can control their body temperature effectively would be animals with a low surface to volume ratio.