Define 'zero population growth rate'. Draw an age pyramid for the same.

Zero population growth rate occurs when the birth rate is equal to the death rate,resulting in no net change in the population size over time.
In an age pyramid representing a stable population (zero growth),the number of individuals in the pre-reproductive and reproductive age groups are approximately equal.
This results in a bell-shaped age pyramid,where the base (pre-reproductive) and middle (reproductive) sections are similar in width,while the top (post-reproductive) section tapers off.