Which of the following contribute to increase in population density?

The correct answer is Option (3) → Natality and Immigration

Option (3) Natality and Immigration — Correct. Population density changes with four processes. Natality (births) and immigration (individuals coming in) add to the population and raise the density; mortality and emigration lower it.

Note: A similar question was also asked in CUET (UG) 2025 on 22-05-2025 (Slot 1).

NCERT Extract:
Population Growth – “The size of a population for any species is not a static parameter. It keeps changing with time, depending on various factors including food availability, predation pressure and adverse weather. In fact, it is these changes in population density that give us some idea of what is happening to the population – whether it is flourishing or declining. Whatever might be the ultimate reasons, the density of a population in a given habitat during a given period, fluctuates due to changes in four basic processes, two of which (natality and immigration) contribute to an increase in population density and two (mortality and emigration) to a decrease.”