Final answer:
Population growth rate (r) is a measure of how fast a population changes in size over time. It takes into account factors such as birth rate, death rate, immigration, and emigration.
Step-by-step explanation:
Population growth rate (r) is a measure of how fast a population changes in size over time. A positive growth rate means the population is increasing, a negative growth rate means the population is decreasing, and a zero growth rate means the population size remains constant. The growth rate takes into account factors such as birth rate, death rate, immigration, and emigration. The formula for population growth rate is r = (b + i) - (d + e), where b is the birth rate, i is immigration, d is the death rate, and e is emigration.