The true statement is:
Ectotherms cannot insulate (stop heat loss from) their bodies but can only control their body temperature by changing location.
Ectotherms, such as reptiles and amphibians, rely on external sources of heat to regulate their body temperature and do not have the internal mechanisms to insulate or generate their own heat. They typically change locations to find suitable temperatures, such as moving into the sun to warm up or seeking shade to cool down.