Processes of Population Change

Correct answer: B. Out-migration is greater than natural increase

The correct answer is B: out-migration is greater than the positive natural increase. Natural increase is calculated as births minus deaths. If births are greater than deaths, this part of the balance is positive. However, total population change also includes migration: total change = births − deaths + in-migration − out-migration. Suppose natural increase is +100 but 150 more people leave than enter. The total change is 100 − 150 = −50, so the population declines. A is wrong because in-migration greater than natural increase would normally add people and support growth, not explain a decline. C is wrong because equal births and deaths would make natural increase zero, not positive. D is wrong because migration can overcome a positive natural increase. Memory cue: positive natural increase does not guarantee total growth; always add the migration balance.

Correct answer: B. In-migration

The correct answer is B: strong in-migration can produce total population growth even when natural increase is negative. Negative natural increase means deaths are greater than births, so births minus deaths has a negative value. Total population change, however, is calculated as births minus deaths plus in-migration minus out-migration. For example, if natural increase is −100 but 250 people enter and only 20 leave, the total change is −100 + 250 − 20 = +130. The population therefore rises. A is wrong because out-migration removes people and would make growth less likely. C is wrong because deaths contribute to the negative natural increase rather than reversing it. D is wrong because a larger area does not itself create additional people; it may affect density, but not the population total. Memory cue: when births are fewer than deaths, look for a positive migration balance.

Correct answer: C. In-migration and out-migration are equal and both are large

The correct answer is C. Net migration is calculated as in-migration minus out-migration. Gross migration refers to the total amount of movement in both directions, usually the sum of arrivals and departures. If 10,000 people enter an area and 10,000 people leave it, net migration is 10,000 − 10,000 = 0, but gross migration is 20,000, which is high. A gives zero net migration but also zero gross migration, so movement is not high. B gives a positive net migration because many people enter and none leave. D gives a negative net migration because people leave without an equal incoming flow. The important distinction is that net migration measures the balance, while gross migration measures the volume of movement. Memory cue: equal large flows cancel in the net figure but remain visible in the gross figure.

Correct answer: A. The reproductive-age group is large

The correct answer is A: a large reproductive-age group can produce many total births even when the birth rate is falling. A rate is a proportion or measure relative to a population, whereas total births are the actual number of babies born. Step one: the birth rate decreases, meaning the average or proportion of births is lower. Step two: if the number of people in the reproductive-age group is very large, even a lower rate applied to that large group can result in many births. This is sometimes called population momentum. A is correct because population size and age composition affect the total. B is wrong because the death rate does not determine how many births occur. C is wrong because migration being possible or impossible is not the main explanation. D is wrong because a large land area does not itself produce births; the number and age structure of people matter. Memory cue: a lower rate multiplied by a much larger base can still give a high total.

Correct answer: A. Mainly young workers move out

The direct answer is A. A dependent population generally includes people who are less likely to be in the working-age group, especially children and older people. Migration is often age-selective, meaning young adults may be more likely to leave a source area for jobs or education. Step by step, if many working-age people move out, the total population in the source area falls and the remaining children and elderly form a larger percentage of that smaller population. A is correct because it can increase the dependency share even if the actual number of dependants does not rise. B is wrong because the arrival of young workers would usually increase the working-age share and lower the relative dependency share. C is wrong because unchanged age groups do not create a new rise in the proportion of dependants. D is wrong because no migration alone does not change the age composition through migration. Memory cue: when workers leave, dependants become a larger share of those left behind.

Correct answer: A. Out-migration causes labour loss but remittances also arrive

The direct answer is A. Migration can produce both a cost and a benefit for the source area. When workers leave, the area may lose labour, skills, and part of its local productive capacity. At the same time, migrants may send money home; these remittances can raise household income and help pay for food, education, health care, housing, or small investments. A is correct because it clearly presents these opposite effects together. B is wrong because if nobody leaves, there is no out-migration effect to analyse. C is wrong because a change in birth rate is a demographic process, not a dual migration effect. D is wrong because a zero death rate is not a description of migration and does not identify two economic consequences. The effects are not automatically equal or positive in every place; the important idea is that labour loss and money received can occur at the same time. Memory cue: migration may take workers away but send income back.

Correct answer: A. When life expectancy rises and the share of elderly people increases

The direct answer is A. A falling death rate often means that people survive for longer, although the exact effect on age structure depends on the wider demographic situation. If life expectancy rises and the proportion of elderly people increases, governments and communities need to plan for pensions, health services, medicines, accessible transport, housing, and social support. Step by step, fewer deaths can allow more people to reach older ages; longer survival can increase the elderly share; a larger elderly share changes service requirements. A is correct because it connects lower mortality with longer life and an ageing population. B is wrong because if all elderly people leave, the local need for elderly services would not rise in the stated way. C is wrong because zero births and deaths alone do not tell us the age composition. D is wrong because an area with no population has no elderly population to plan for. Memory cue: longer lives can change the age structure, not just the total number.

Correct answer: A. The total number is the same but the share of children is rising

The direct answer is A. Total population tells us how many people there are, but it does not show how those people are distributed by age. A place can have the same total number while its age composition changes. If the share of children rises, the area may need more schools, vaccination, child health services, teachers, and childcare, even though the total population appears stable. A is correct because looking only at the unchanged total could hide an important change in population structure and service needs. B is wrong because unchanged total number and unchanged composition do not provide a hidden demographic change. C is wrong because if births, deaths, and migration are all absent, the stated population components are not producing a change. D is wrong because different age groups do not usually have identical service needs; the option also does not describe a misleading total. Memory cue: always examine both population size and population composition.

Correct answer: A. When births, deaths, migration, time period, boundary and composition are all examined

The correct answer is A. Evidence-based population analysis uses several relevant dimensions instead of relying on one number. Births and deaths show natural change, while in-migration and out-migration show the movement component. The time period tells us whether the change is short-term or long-term, and the boundary tells us which area is being measured. Population composition, such as age or sex structure, helps explain who is affected and how future change may occur. B is incomplete because birth rate alone ignores deaths and migration. C is unjustified unless reliable evidence shows that migration is zero. D is not analysis because it lacks supporting data. A careful student should ask what changed, where, during which period, and through which component. Memory cue: complete analysis combines components, context and composition.

Correct answer: B. Future natural increase may also be affected

Direct answer: B is correct. A falling birth rate tends to reduce natural increase, but population structure also matters. Young migrants add people who may belong to, or soon enter, the reproductive-age groups. If they form families in the receiving area, the number of future births may be different from what the falling birth rate alone suggests. Migration can therefore affect both the present total population and its future age composition. Option A is too absolute: growth need not stop because migration and other demographic factors continue. Option B is possible because a larger young population can influence future births and natural increase. Option C is unsupported; young in-migration does not necessarily make the death rate rise. Option D is wrong because population depends on demographic processes, not only area. Memory cue: age-selective migration changes the age structure, and age structure affects future births.

Correct answer: B. When deaths are much more than births and in-migration is small

Direct answer: B is correct. Total population change has two broad parts: natural change, which is births minus deaths, and net migration, which is in-migration minus out-migration. A positive net migration adds people, but it may be smaller than the natural decrease caused by deaths greatly exceeding births. For example, if natural change is −100 and net migration is +40, the total change is −60, so the population declines. Option A would create positive natural increase and does not support decline by itself. Option C gives zero natural change, so positive net migration would normally raise the total. Option D means out-migration is zero; unless other conditions are unusual, it does not explain a decline when migration is positive. Memory cue: add the signed values—positive migration can be outweighed by a larger negative natural change.

Correct answer: B. When death rate and out-migration are both high

Direct answer: B is correct. A high birth rate is only one part of population change. Total growth also depends on deaths and migration. If the death rate is high, many people are removed through natural decrease relative to births. If out-migration is also high, additional people leave the region. These two forces can greatly reduce or even cancel the increase suggested by a high birth rate. Option A would add more people through in-migration, so it would generally strengthen total growth rather than hide it. Option C may reduce deaths and support population growth, although its exact effect depends on other factors. Option D can reduce deaths among infants and may also support growth; it does not explain why high births fail to show total growth. Memory cue: birth rate is one indicator, not the whole population balance.

Correct answer: A. When deaths exceed births but in-migration is very high

Direct answer: A is correct. Negative natural increase means that deaths exceed births, so the natural component reduces the population. However, a city can still grow if enough people move into it. Total population change equals natural increase plus net migration. For example, a natural decrease of 2,000 combined with net in-migration of 5,000 produces a total increase of 3,000. Option B would usually reduce the population further because more people leave. Option C gives zero natural change and no migration, so the total should remain unchanged. Option D incorrectly treats death rate and population density as the same concept: death rate measures deaths in relation to population over time, while density measures people per unit area. Memory cue: a large positive migration balance can overcome a negative natural balance.