Processes of Population Change

Direct answer: Option A—if births exceed deaths, population increases naturally even when net migration is zero. Net migration is zero when in-migration equals out-migration, so movement has no net effect on the population size. Natural increase is calculated separately as births minus deaths. For example, with 1,200 births and 900 deaths, natural increase is +300. If the same number of people enter and leave, net migration is 0, so total change remains +300. Option A is correct. Option B gives a natural decrease. Option C gives zero natural increase, so with zero net migration there is no change. Option D is not a condition explaining population growth and cannot provide a positive increase. Common confusion: zero net migration means balanced movement, not zero births or deaths.

Direct answer: Option A—an increase of 300 people. Solve the two components separately. First, natural increase = births − deaths = 1,500 − 1,500 = 0. Second, net migration = in-migration − out-migration = 400 − 100 = +300. Total population change = natural increase + net migration = 0 + 300 = +300. Therefore the population increases by 300. Option A is correct. Option B ignores the positive net migration. Option C reverses the migration balance; more people enter than leave, so migration cannot reduce the population. Option D incorrectly adds all figures without subtracting deaths and out-migration. A useful method is to write the formula before calculating: total change = (births − deaths) + (in − out).

Direct answer: Option A—total change is zero. Calculate natural increase first: births − deaths = 1,200 − 900 = +300. Then calculate net migration: in-migration − out-migration = 250 − 550 = −300. Add the two components: +300 + (−300) = 0. The natural growth is exactly cancelled by the net loss through migration. Option A is correct. Option B reports only the natural increase and forgets the migration loss. Option C adds the two positive-looking differences incorrectly instead of treating excess out-migration as negative. Option D reports only the size of the migration loss and ignores the natural increase. A negative net migration does not always produce a total population decrease; it can be balanced by positive natural increase. Memory cue: calculate births–deaths and in–out separately, then add signed results.

Direct answer: Option A—the listed data provide a broad basis for planning population-related services. Births and deaths show natural change; in-migration and out-migration show movement; age structure helps estimate the types of services different groups may need; and a time period allows trends and changes to be measured. Together, these data can support planning for food, schools, health services, housing, and other public needs. Option A is correct because it includes demographic processes, population composition, and time. Option B contains useful physical-geography information in some contexts but does not describe population needs. Option C is too limited and lacks population counts and processes. Option D concerns soil and crops, not the main demographic information required here. Memory cue: good population planning needs change, movement, composition, and time—not one isolated fact.

Direct answer: Option B is correct. Population change is not decided by births alone. First, natural change is found by subtracting deaths from births: natural change = births − deaths. Then migration is included. In-migration adds people to the area, while out-migration removes people from it. Therefore, actual population change = births − deaths + in-migration − out-migration. For example, if births exceed deaths by 500 but 800 more people leave than enter, the actual change is 500 − 800 = −300, so the population decreases by 300. Option A is wrong because it ignores deaths and migration. Option C is wrong because area helps calculate density but does not by itself change the number of people. Option D is wrong because weather may influence movement, but it is not the population-change calculation. Remember: count natural increase and net migration together.

Direct answer: Option C is correct. Natural increase means births minus deaths. It is positive when births are greater than deaths. However, total population also depends on migration. The complete relationship is total change = natural increase + in-migration − out-migration. Suppose natural increase is +200, but 500 more people leave than enter. The total change is 200 − 500 = −300, so the population decreases. Option A is wrong because high in-migration adds people and normally increases total population. Option B describes a negative natural increase, not a case in which natural increase is positive. Option D is wrong because with no migration, a positive natural increase would make the population rise, not fall. The important distinction is between natural increase and actual or total population change. A positive birth-death balance cannot prevent decline if outward movement is larger.

Direct answer: Option B is correct. Actual population change has two parts: natural change and net migration. Natural change is births minus deaths because births add people and deaths remove people. Net migration is in-migration minus out-migration because arrivals add residents and departures reduce residents. Combining both gives actual change = births − deaths + in-migration − out-migration. Option A is wrong because deaths and out-migration are losses, so they must be subtracted rather than added. It also treats migration as one unclear quantity. Option C is a relationship used to find population from area and density, not the change in population over time. Option D compares weather-related quantities and has no role in this demographic formula. Pay attention to the signs: additions have plus signs and reductions have minus signs. The memory cue is “born and in, add; dead and out, subtract.”

Direct answer: Option B, 400, is correct. Use the complete formula: actual change = births − deaths + in-migration − out-migration. Substitute the values step by step: 900 − 400 + 250 − 350. First calculate natural change: 900 − 400 = 500. Next calculate net migration: 250 − 350 = −100, because 100 more people leave than enter. Finally, combine them: 500 + (−100) = 400. Thus the population increases by 400 people. Option A, 300, does not result from the given balance. Option C, 500, is only the natural change and wrongly ignores migration. Option D, 1,400, adds all the figures, even though deaths and out-migration must be subtracted. A reliable method is to mark births and in-migration as additions and deaths and out-migration as reductions before calculating.

Direct answer: Option B is correct. Internal migration means movement within the same country, so it does not change the national total directly, but it can strongly change where people live. Large-scale movement from villages to cities removes many residents from rural areas and adds them to urban areas. Consequently, the population distribution becomes more urban, and the densities of the source and destination areas change. Option A may move people only a short distance within one locality, so its effect on the broad village-city distribution is small. Option C concerns births and deaths, not the movement of people between places. Option D describes no migration and therefore cannot change distribution through migration. Remember to identify both the origin and destination: a large flow from a rural origin to an urban destination has a much greater distributional effect than a small local move.

The correct answer is A: natural increase may become rapid. Natural increase means the number of births minus the number of deaths during a period; it does not include migration. First, a high birth rate continues to add many people. Next, when the death rate falls, fewer people are removed from the population. Therefore, the gap between births and deaths becomes wider and the natural increase can become faster. For example, if the birth rate is 30 per 1,000 people and the death rate falls from 15 to 8, natural increase changes from 15 to 22 per 1,000. Option A is correct because it describes this possible widening of the gap. Option B is wrong because the difference is not automatically zero; it is positive when births exceed deaths. Option C is wrong because high births and fewer deaths generally push population upward, although migration could affect total population separately. Option D is wrong because birth and death rates do not stop migration. Memory cue: natural increase = births − deaths; total population change also considers in-migration and out-migration.

The correct answer is A: out-migration of young workers. The working-age group consists broadly of people who are able to participate in economic activities. A source area is the place from which people leave. When young workers move from that area to another place for jobs, education, or other reasons, they are removed from the source area’s working-age population. This can reduce the available labour force and may create shortages in farms, factories, shops, or services. Option A is correct because it describes age-selective movement directly. Option B is wrong because the birth of children adds people to a younger age group, not immediately to the working-age group. Option C is wrong because in-migration brings people into the area and generally increases, rather than reduces, its population. Option D is wrong because a decline in death rate usually helps more people survive and does not specifically remove young workers. The effect is not always identical in every place, because the age and number of migrants matter. Memory cue: out-migration takes people out; in-migration brings people in.

The correct answer is B: the source area may experience both labour loss and income through remittances. Out-migration means that people leave their usual area, so the source area may lose workers, especially when many working-age people depart. Money sent by migrants to their families or communities is called a remittance. These funds can help pay for food, education, health care, housing, debt repayment, or small businesses. Thus migration can create a social or labour cost while also bringing financial support. Option A is wrong because it notices the possible population decline but ignores the economic benefit of remittances. Option B is correct because it includes both effects and does not claim that either one must occur in exactly the same amount everywhere. Option C is wrong because out-migration does not always increase the source population. Option D is wrong because remittances have no power to end deaths or eliminate the death rate. Memory cue: migrants may take labour away but send income back.

The correct answer is B: pressure is greatest when many people arrive in a short time and services are limited. In-migration adds people to a destination area. If arrivals are sudden and large, the existing supply of houses, drinking water, sanitation, schools, hospitals, transport, and jobs may not expand quickly enough. As a result, each service has to serve more people, so pressure rises. Option A is wrong because a small, gradual arrival can often be managed when facilities are adequate. Option B is correct because it combines a rapid increase in demand with limited capacity. Option C is wrong because no arrivals create no additional in-migration pressure. Option D is wrong because a falling population does not describe the condition of heavy in-migration; it may even reduce demand. The exact effect depends on planning and investment, but the stated combination is the most likely to create immediate pressure. Memory cue: pressure depends on both the number and speed of arrivals compared with service capacity.

The correct answer is B: in-migration is greater than the negative natural increase. Natural increase equals births minus deaths. If deaths are greater than births, natural increase is negative, which is called natural decrease. However, total population change also includes net migration. In simple form, total change = births − deaths + in-migration − out-migration. For example, if births minus deaths equals −100 but net in-migration equals +250, the total change is +150, so population increases. Option A is wrong because heavy out-migration would normally reduce population further, unless another large inflow counteracted it. Option B is correct because an inflow larger than the natural decrease produces a positive total change. Option C is wrong: if births and deaths are both zero, natural increase is zero, not negative. Option D is wrong because a change in area may alter density calculations but does not itself add people. Memory cue: natural decrease can be overcome by a larger net inflow.

The correct answer is A: 100. To find total population change, combine natural change and net migration. Natural change is births minus deaths: 300 − 500 = −200. Net migration is in-migration minus out-migration: 400 − 100 = +300. Now add the two results: −200 + 300 = +100. The plus sign means that the population increases by 100 people during the stated period. Option A is correct. Option B is wrong because it represents only the size of the natural decrease, not the final total change. Option C is wrong because it uses the net migration alone and ignores the 200-person natural decrease. Option D is wrong because it does not correctly combine the four figures and treats the values as if they should simply be added without subtracting deaths and out-migration. A useful general formula is: total change = births − deaths + in-migration − out-migration. Memory cue: additions are births and arrivals; removals are deaths and departures.

The correct answer is A: the effect of migration may be missed. Natural increase measures only births minus deaths. It tells us whether a population is growing or declining because of natural demographic events, but it does not tell us how many people entered or left the area. To understand actual population change, we should also consider net migration, which is in-migration minus out-migration. For example, a place may have a positive natural increase but still lose population if many more people leave than enter. Conversely, a place with natural decrease may grow if it receives enough migrants. Option A is correct because ignoring migration gives an incomplete picture. Option B is not a limitation; births and deaths are exactly the components included in natural increase. Option C is wrong because density requires population and area data and cannot be obtained automatically from births and deaths. Option D is wrong because natural increase does not change the physical area. Memory cue: natural increase counts births and deaths; total change also counts movement.

The correct answer is B: people may become concentrated in a small urban centre. Total population and population distribution are different ideas. Total population tells us how many people live in the whole area, while density describes how many people occupy a unit of area. If the total number remains unchanged but people move from scattered villages or wider spaces into one small town, the town’s local density rises. This can increase pressure on housing, roads, water, sanitation, schools, and health services even though the total population has not increased. Option A is wrong because spreading people evenly would usually reduce concentration and local pressure. Option B is correct because concentration places more people in a smaller space. Option C is wrong because if everyone leaves, the local population and pressure fall rather than rise. Option D is wrong because no spatial change would not create new local concentration. Memory cue: stable total does not mean stable distribution.

The correct answer is B: drawing a conclusion only from the birth rate makes the assessment incomplete. Population change depends on several connected factors. Births add people, deaths remove people, in-migration adds residents, and out-migration removes residents. The time period and the boundary of the area also matter because a rate has meaning only when its population and time reference are clear. Looking only at the birth rate ignores deaths and migration, so it cannot show the actual increase or decrease in total population. Option A is wrong because it includes the main components and the time period. Option B is correct because one indicator alone cannot explain the full change. Option C is wrong because natural increase and net migration together provide a useful framework for total change. Option D is wrong because a clear boundary improves measurement rather than making it incomplete. Memory cue: births and deaths show natural change; migration completes the population picture.

Direct answer: Option A, mainly migration-based increase. Population change has three important components: births, deaths and migration. Natural increase is calculated by subtracting deaths from births. When both the birth rate and death rate are low, this natural increase may be small. However, in-migration means that people are entering the area from other places. These incoming people add to the population, so the total population can rise mainly because of migration. Option A is correct because it identifies the main source of growth. Option B is wrong because a low death rate does not by itself produce decline. Option C is wrong because it ignores the strong effect of in-migration and confuses natural increase with total population change. Option D is wrong because high in-migration can make the population grow even when births and deaths are both low. Memory cue: natural change equals births minus deaths; total change also includes migration.

Direct answer: Option B. Natural increase is the difference between the number or rate of births and the number or rate of deaths. Therefore, high birth and death rates do not automatically mean high natural increase. Suppose there are 40 births and 38 deaths per thousand people. Both figures are high, but the difference is only 2 per thousand, so the natural increase is low. Option A is wrong because births much greater than deaths create a large natural increase. Option B is correct because a small gap leaves only a small addition after deaths are subtracted from births. Option C is wrong because in-migration affects total population, not natural increase, which uses only births and deaths. Option D is also wrong because zero out-migration does not determine the birth-death difference. Memory cue: high rates can still produce low growth when they are nearly equal.

Direct answer: Option A. When the death rate falls, more people survive, and the size of the population may increase rapidly if births remain significant. A larger population needs more drinking water, sanitation, houses, schools, health facilities and public-health education. Planning these services early helps prevent overcrowding, unsafe water use and pressure on existing facilities. Option A is correct because health education, water supply and housing respond directly to the needs of a growing population. Option B is wrong because measuring mountains does not provide an essential population service. Option C is not a real response to population growth and has no role in service planning. Option D is wrong because stopping the census would remove important information needed to estimate population size and plan facilities. The question asks what becomes immediately important, so choose basic services rather than an unrelated physical-geography activity. Memory cue: falling deaths mean more survivors, and more survivors require more services.

Direct answer: Option A. In-migration brings people into a receiving area. It can create pressure if facilities are inadequate, but it can become an advantage when migrants are able to use their skills in suitable work. Employed and skilled migrants may add labour, knowledge, entrepreneurship and demand for goods and services. They can contribute to production and support the local economy. Option A is correct because skills and employment help convert population movement into a productive demographic resource. Option B is wrong because the absence of services makes settlement and integration difficult. Option C is wrong because a complete lack of housing creates insecurity and overcrowding rather than an advantage. Option D is wrong because without jobs, migrants may face unemployment and the receiving area may experience additional social and economic pressure. The benefit is not automatic; it depends on opportunities, facilities and effective planning. Memory cue: migration becomes an asset when people can participate productively, not merely when they arrive.

Direct answer: Option B. In-migration increases the number of people living in the receiving city. If housing, water, sanitation, transport, schools, health facilities and jobs do not grow enough to meet this additional demand, the city may face overcrowding, informal settlements, unemployment and pressure on infrastructure. Option B is correct because insufficient facilities make it difficult to absorb newcomers safely and productively. Option A is wrong because adequate housing, services and employment help manage migration rather than create a problem. Option C is generally not the best answer because a very small inflow is less likely to create major citywide pressure. Option D is wrong because natural increase being zero does not remove the effect of people arriving from elsewhere. The key comparison is between the size of in-migration and the receiving city’s capacity. Memory cue: migration is beneficial or problematic partly according to whether urban capacity keeps pace with arrivals.

Direct answer: Option A. Age-selective out-migration means that people of particular age groups, often working-age people, are leaving an area in greater numbers than other groups. This can change the size and composition of the remaining population. It may reduce the local workforce and increase the relative share of children or older dependants, affecting the dependency ratio and service needs. Therefore, planners should check migrants’ ages and work status, and compare them with the age and employment structure of those who remain. Option A is correct because it reveals which population groups are leaving and whether the area is losing workers. Options B, C and D concern physical geography and do not show the demographic composition of migration. Memory cue: when migration is age-selective, always inspect who is moving, especially age and work participation, not just the total number.

Direct answer: Option A. International migration occurs when people move across the national boundary of one country to live or settle in another country. Step 1 is to identify whether a country-to-country border has been crossed. Step 2 is to distinguish migration from a short visit or temporary travel; the question describes people settling. Step 3 is to see the population effect: the receiving country gains people and the sending country loses people, apart from any later births or deaths. Option A gives exactly this condition. Option B is local or internal movement because no national border is crossed. Option C concerns the relationship between births and deaths and says nothing about migration. Option D rules out movement altogether, so it cannot describe international migration. Memory cue: international means between nations; crossing a national border is the essential clue.