The study of human population statistically is known as

Infant mortality rate is minimum in:

The best solution to the population problem in India is to

Higher human population in cities is mainly due to

The world population in $1900$ was ........ billion,which increased rapidly to ........ billion in $2000$ and reached ........ billion in $2011$.

Which of the following can be taken as characteristic demographic features of the developing countries?
$(a)$ High fertility rate
$(b)$ Rapidly rising mortality rate
$(c)$ Very young age distribution
$(d)$ Rapid population growth
$(e)$ Rapidly falling mortality rate
$(f)$ Very old age distribution