What is formed by the aggregation of individual organisms of the same species?

List any three important characteristics of a population and explain.

Which of the following are useful for measuring population density (size)?
$(a)$ Numbers
$(b)$ Biomass
$(c)$ Pug marks
$(d)$ Height

The crude number of births by a population per unit time is called:

If there were $30$ lotus plants in a pond last year and through reproduction $10$ new plants were added, taking the current population to $40$, then the birth rate = $.........$ offspring per lotus per year.

$A$ biologist studied the population of rats in a barn. He found that the average natality was $250$, average mortality $240$, immigration $20$ and emigration $30$. The net increase in population is