Final answer:
The demographic equation used for determining population size is [B+E] - [D+1], taking into account births, deaths, and migration. Understanding the per capita birth rate (bN) and death rate (dN) is crucial in calculating population changes over time, particularly when assessing negative growth.
Step-by-step explanation:
The equation for determining the population size is found by calculating the births minus deaths plus (or minus) net migration, commonly known as the demographic equation. This formula for population change is an essential tool in demographics to help determine the growth rate and, by extension, which stage in the demographic transition model a country might be in. The correct choice with the variables as presented in the student's options would be [B+E] - [D+1] where 'B' would represent births, 'D' for deaths, and 'E' to represent some form of net migration or similar component.
Analyzing a given table with birth rates and death rates can reveal populations experiencing a negative change in population size when the death rate exceeds the birth rate. Additionally, understanding the per capita birth and death rates, represented conventionally as 'bN' for births and 'dN' for deaths, provides insights into the instantaneous growth rate of the population, using differential calculus to express these changes per unit of time.