Define the following terms:
$(1)$ Immigration
$(2)$ Emigration
$(3)$ Mortality

(N/A) $(1)$ Immigration: It is the number of individuals of the same species that have come into the habitat from elsewhere during the time period under consideration.
$(2)$ Emigration: It is the number of individuals of the population who left the habitat and gone elsewhere during the time period under consideration.
$(3)$ Mortality: It is the number of deaths in the population during a given period.