Question

why is it important to know about the population of a country give 3 reasong

Answer 1

if there is any sudden growth in population it can be understood that there is migration from other countries
a sudden decrease in population would mean that there may be health problems in the country
....sorry but i know these two reasons

Answer 2

it is important for a country to know about its population because;
-to know the amount of literate people
-to know whether the population rise is decreasing or increasing even more
-to make policies that will be beneficent for the nation as a whole 
-to know at what rate the wealth of the nation is getting consumed