Assertion : Ectotherms are able to remain active under cold conditions. Reason : Ectotherms are able to maintain a constant internal temperature, even when the temperature outside fluctuates.

Step-by-step solution

Ectotherms or cold-blooded animals, cannot regulate their body temperature and are unable to maintain a constant internal temperature. Their body temperature tends to match with the environmental temperature in which they live, (e.g., frogs and snakes). These animals are not able to remain active under cold conditions.