Certain characteristic demographic features of developing countries are:

Define population and community.

Information on birth-rate,death-rate,sex-ratio,and age distribution of a population can be obtained from:

Select the correct option based on the number and size of offspring produced by the following organisms:
$I -$ Oysters,$II -$ Birds,$III -$ Pelagic fishes,$IV -$ Mammals
(Many small-sized offspring) $\quad$ (Few large-sized offspring)

Factors related to increase in population density are $:-$

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 :