$A$ biologist studied a rat population at the time of birth. He observed that the estimated births were $250$, estimated deaths were $240$, $20$ rats immigrated into the population, and $30$ rats emigrated from the population. What was the net increase in the population?

Which factors affect the population size in a specific habitat?

In the given figure,which factors are responsible for the increase in population density?

The aggregate of processes that determine the size and composition of any population is called:

The different age groups in a population are classified by:

Read the following statements and choose the option with all the correct statements only :
$(A)$ The size of a population for any species is not a static parameter.
$(B)$ Total number is always the most appropriate measure of population density because in all cases it is most meaningful and easy to determine.
$(C)$ $A$ population growing in a habitat with unlimited resources shows initially a lag phase followed by phases of acceleration and deceleration and finally an asymptote.
$(D)$ According to ecologists,life history traits of organisms have evolved in relation to the constraints imposed by the abiotic and biotic components of the habitat in which they live.
Choose the correct answer from the options given below :