Answer:
The rate of reproduction.
Explanation:
It should be understood that poiklothermic animals are the animals that do not have constant body temperature. This means that their temperature changes in accordance to the temperature of the environment. Examples of such organisms are reptiles and Pisces, fishes, among others.
The homeothermic animals are the animals that are capable of maintaining their body temperature.
Homeotherm is usually applied to animals that can maintain a constant body temperature through metabolic processes endotherms.
It should be understood that endothermy is the process of maintaining body temperature through internally generated metabolic heat
Examples of endothermic homeotherms are bird and mammals, these animals have a high metabolic rate.
In conclusion, the population of poiklothermic animals are more than that of homeothermic animals because of the rate of their reproduction. The poiklothermic animals reproduce in high numbers when compared to the the homeothermic animals.