question_answer 32)

  Which of the following would necessarily decrease the density of a population in a given habitat? (a) Natality> mortality                                                    (b) Immigration > emigration (c) Mortality and emigration                                       (d) Natality and immigration

Answer:

                  (c) Population growth means increase in its size and is determined by addition and loss of individual in a population. Population density is the number of individuals present per unit volume/area at given time. Thus, mortality and emigration would necessarily decrease the density of a population in a given habitat due to loss of individual result from mortality (deaths) and emigration. When natality rate will be more than mortality rate and increased immigration rate mould necessarily increase the density of a population.