Which of the following options correctly defines natality?

The correct answer is Option (2) → The number of births during a given period in the population

Population density changes through four basic processes. Two add individuals: natality (births) and immigration (arrivals). Two remove individuals: mortality (deaths) and emigration (departures).

Option (1) The number of individuals of the population who left the habitat — Incorrect. Individuals that leave the habitat and go elsewhere make up emigration. It lowers population density.

Option (2) The number of births during a given period in the population — Correct. Natality is the number of births in the population during a given period. These births are added to the initial density, so natality raises the population.

Option (3) The number of deaths in the population during a given period. — Incorrect. The number of deaths during a given period is mortality, the opposite of natality.

NCERT Extract:
Population Growth – “… 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.
(i) Natality refers to the number of births during a given period in the population that are added to the initial density. (ii) Mortality is the number of deaths in the population during a given period. … (iv) Emigration is the number of individuals of the population who left the habitat and gone elsewhere during the time period under consideration.”