Which of the following flowers only once in its life-time?

If a population growing exponentially double in size in $3$ years, what is the intrinsic rate of increase $(r)$ of the population?

If the mean and the median pertaining to a certain character of a population are of the same value, the following is most likely to occur

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

Population growth of a country depends upon