Explanation:

• Natality refers to the number of births during a given period in the population that are added to the initial density. Natality contributes to an increase in population density.
• Mortality is the number of deaths in the population during a given period. It contributes to a decrease in population density.
• Immigration is the number of individuals of the same species that have come into the habitat from elsewhere during the time period under consideration. It contributes to an increase in population density.
• Emigration is the number of individuals of the population who left the habitat and went elsewhere during the time period under consideration. It contributes to decrease in population density.
• So, option d is the correct answer