EVERYDAY SCIENCE

Detailed explanation-1: -In the long term, zero population growth can be achieved when the birth rate of a population equals the death rate. That is, the total fertility rate is at replacement level and birth and death rates are stable, a condition also called demographic equilibrium.

Detailed explanation-2: -World population will stop growing when the birth rate equals the death rate; no one knows whether this will happen. The birth rate and the death rate would eventually reach equilibrium several decades after couples average two children each.

Detailed explanation-3: -When the number of births are equal to the number of deaths, the population size is not increasing and the population has reached a stationary phase or plateau phase.

Detailed explanation-4: -If a population exhibits a higher birth rate than death rate, the population size will increase. This is because more individuals are being added than are dying. The population size will remain constant if the birth rate and death rate are equal.

Detailed explanation-5: -At carrying capacity, because population size is approximately constant, birthrates must equal death rates, and population growth is zero.