At present,the total population of the world is about:

The $20^{th}$ century has witnessed a remarkable increase in the population of the world and especially in India. One major factor for this is that

The greatest biological problem faced by human beings is:

The term population explosion means

Choose the correct causes for the population growth.
$I$. Decline in death rate
$II$. Rapid increase in $MMR$ and $IMR$
$III$. Rapid decline in $MMR$ and $IMR$
$IV$. Increase in the number of people in the reproductive age group
$V$. Rapid increase in the death rate

July $11$ is observed as