Answer
See the sample answer below.
Work Step by Step
An exponential growth model has the form $f(t)=Ab^{t}$,
and, when b is a value over 1, the function values become extremely high as t increases.
If we use such a model for population growth, it can be used only for a limited time, because as population grows, for example, the food production can not follow indefinitely, so the whole population can not survive with reduced food resources per person.
The exponential curve eventually "bends" to a value after which resources can not support any significant future growth.
In other words, after a certain time $t$, the exponential model will no longer be applicable.
