Which of the following would necessarily decrease the density of a population in a given habitat?

1. Natality> mortality

2. Immigration> emigration

3. Mortality and emigration

4. Natality and immigration

(c) Population growth means an increase in its size and is determined by the addition and loss of the individual in a population. Population density is the number of individuals present per unit volume/area at a given time.

Thus, mortality and emigration would necessarily decrease the density of a population in a given habitat due to the loss of individual results from mortality (deaths) and immigration.

When the natality rate will be more than the mortality rate and increased immigration rate mold necessarily increases the density of a population.