Final answer:
Immigration increases population size and density, while emigration decreases population size and density.
Step-by-step explanation:
The immigration and emigration of individuals can impact the density of different populations. Immigration refers to the movement of individuals into a specific area to take up permanent residence, while emigration is the movement of individuals out of an area to another place of permanent residence. When individuals immigrate into a population, it increases the population size and density. On the other hand, when individuals emigrate out of a population, it decreases the population size and density. For example, if a large number of people immigrate to a city, the population size and density of that city will increase. This can result in increased competition for resources, such as housing and jobs. Conversely, if a large number of people emigrate from a city, the population size and density will decrease, which may lead to a decrease in demand for goods and services. In summary, immigration and emigration can have a significant impact on the density of different populations. Immigration increases population size and density, while emigration decreases population size and density.