What are the four basic processes that contribute to changes in population density?

Birth rate, death rate, immigration, emigration

The correct answer is: a) Birth rate, death rate, immigration, emigration

The four basic processes that contribute to changes in population density are birth rate, death rate, immigration, and emigration.

1. Birth rate: The rate at which new individuals are born into the population. It increases the population size.
2. Death rate: The rate at which individuals die within the population. It decreases the population size.
3. Immigration: The movement of individuals into a population from another population or habitat. It increases the population size.
4. Emigration: The movement of individuals out of a population to another population or habitat. It decreases the population size.

These processes affect the population density by influencing the number of individuals present in a given habitat or area over time. By understanding and studying these processes, ecologists can gain insights into the dynamics and changes in population size and density.