If you are told a population has a mean of 25 and a variance of 0, what must you conclude?

By definition, variance is the measure in which elements in a population or sample are spread from the average or mean value. Additionally, mean is summation of all elements divided my the number of elements.

In this regard, a mean of 25 and a variance of 0 will mean that all the elements in that population are equal to 25.