Here's the question you clicked on:
brittanylyn1993
6. A country that has a stable population is characterized by an age structure that is _____.
I suspect the answer is 'unchanging'... http://en.wikipedia.org/wiki/Population_pyramid Lotkai proved that the age distribution of any population that is subject, for a sufficiently long time, to constant fertility and mortality becomes fixed. He called this end-product of constant demographic conditions a "stable population", characterized both by an unchanging age distribution and by a fixed annual rate of natural increase