In which situation can total population change be zero?

Correct answer: When deaths and out-migration equal births and in-migration

Direct answer: A, when deaths and out-migration equal births and in-migration. Total population change is affected by four flows: births add people, in-migration adds people, deaths remove people and out-migration removes people. In a simple balance, total change is births plus in-migration minus deaths minus out-migration. If the two adding processes together exactly equal the two reducing processes together, the result is zero. This does not mean that no births, deaths or movement occurred; it means their combined effects cancelled each other during the period considered. B would produce an addition from births unless other losses exactly balanced it, but no such balance is stated. C normally adds population, and D removes two possible losses rather than guaranteeing balance. Memory cue: zero change means total additions equal total reductions.