Any species growing ...$A$... under unlimited resource conditions can reach enormous population densities in a short time. Darwin showed how even $\ldots$ $B$... growing animal like elephant could reach enormous numbers in absence of check and that characteristics of organism is called $C$
Choose the correct option for $A , B$ or $C$ respectively
If natality is represented by $-B$
If mortality is represented by $-D$
If immigration is represented by $-I$
If emigration is represented by $-E$
If population density is represented by $-N$
Then population density at time $t+1$ is represented by
In India, if the marriage age is changed to $21$ years then
The primary cause behind rapidly growing population of the world in recent times is