Processes of Population Change

Correct answer: A. By the difference between births and deaths

Answer: A, the difference between births and deaths. Natural increase means the change produced naturally within a population, so we compare the number of live births with the number of deaths during a particular period. In simple form: natural increase = births − deaths. Migration is not included in this measure; migration is studied separately as movement into or out of a region. A is correct because it gives the exact basis of natural increase. B is wrong because in-migration and out-migration describe migration balance, not natural increase. C is related to population density, not natural increase. D contains population characteristics, but literacy and sex ratio do not calculate natural increase. Memory cue: natural means births and deaths; total change also adds migration.

Correct answer: B. In-migration

Answer: B, in-migration. In-migration occurs when people enter a city or region from another place, often to find employment, education, services, or better living conditions. Even if the city has few births, its total population can grow when more people arrive than leave. A is not the best answer: negative natural increase would mean deaths exceed births, but it does not explain the continuing arrival of workers. B directly names the process described in the question. C would generally reduce population growth rather than cause it. D concerns the size of land, not the number of residents. Remember the distinction: births minus deaths produce natural increase, while people entering minus people leaving produce migration change.

Correct answer: D. Births are more than deaths

Answer: D, when births are more than deaths. Natural increase is calculated by subtracting deaths from births. If the result is greater than zero, natural increase is positive. For example, if a population has 1,000 births and 700 deaths, the natural increase is 300. A gives the opposite situation, so the result is negative. B gives a result of zero, not a positive increase. C concerns out-migration, which affects total population change but is not part of natural increase. D correctly states the required relationship between births and deaths. A useful rule is: births greater than deaths means positive natural increase; births equal to deaths means zero; births fewer than deaths means negative.

Correct answer: C. Improvement in vaccination and medical facilities

Answer: C, improvement in vaccination and medical facilities. Death rate measures deaths in relation to the population during a specified period. Vaccination helps prevent certain infectious diseases, while medical facilities support diagnosis, treatment, emergency care, and management of illness. Therefore, better public health can directly reduce avoidable deaths and lower mortality. A may change the number of people in a place but does not directly improve survival there. B changes the physical area, not health conditions or the death rate itself. D is only a measurement or calculation; counting density cannot reduce deaths. C is the only option that directly addresses disease prevention and treatment. Memory cue: to reduce mortality, think prevention plus treatment—not area or population counting.

Correct answer: A. Positive

Direct answer: A, positive. Net migration measures the balance between people entering and people leaving a region. The basic relationship is: net migration = in-migration minus out-migration. If more people enter a district than leave it, the subtraction gives a number greater than zero, so net migration is positive. This usually indicates a population gain from migration, although total population also depends on births and deaths. B would be correct only if out-migration were greater than in-migration. C would apply when the two flows were equal. D is incorrect because the information given is sufficient to determine the sign of net migration. For example, if 1,000 people enter and 400 leave, net migration is +600. Memory cue: incoming minus outgoing; the larger side decides the sign.

Correct answer: B. Population loss

Direct answer: B, population loss. Net migration is calculated as in-migration minus out-migration. When more people leave a region than enter it, the result is less than zero, so the region has negative net migration. Negative net migration indicates a loss of population through movement, even though births and deaths may affect the total population separately. A is the opposite situation and would occur when in-migration is greater than out-migration. C refers to natural increase, which is the difference between births and deaths and does not describe migration. D is also unrelated because the number of people leaving does not itself show that the birth rate has risen. For example, if 800 people leave and 300 enter, net migration is 300 − 800 = −500. Memory cue: more leaving than entering gives a minus sign and a population loss.

Correct answer: C. Birth rate

Direct answer: C, birth rate. Family planning helps individuals or couples decide the number and spacing of children. By preventing unintended pregnancies or spacing births, it can reduce the average number of births and therefore influence the birth rate. This is a fertility-related process, not a movement of people or a direct measure of deaths. A is incorrect because death rate concerns deaths in a population. B and D are incorrect because they describe people leaving or entering a place, while family planning does not itself cause migration. A change in birth rate can affect natural increase, which is calculated from births and deaths, and over time it can influence population growth. The effect depends on people’s choices and access to information and services, so family planning does not mean that births become zero. Memory cue: family planning plans families and therefore mainly affects births.

Correct answer: A. Expansion of housing and basic services

Direct answer: A. Rapid in-migration increases the number of people who need places to live and access to water, sanitation, roads, transport, schools and health facilities. If city planning does not expand these services, overcrowding, informal settlements, pressure on water supply and poor sanitation may develop. Housing and basic services are therefore an immediate planning concern. B is wrong because changing a river is not the normal first response to population growth caused by migration. C is unrelated to providing services for incoming residents. D is wrong because a census should not be stopped; population information is useful for planning. The exact challenge can vary between cities, but housing and essential services are a safe and direct answer. Memory cue: more residents require more homes and services.

Correct answer: B. Because disease prevention and treatment become better

Direct answer: B. Death rate measures deaths in relation to the population during a specified period. Health improvements can reduce deaths by preventing disease, detecting illness earlier and providing more effective treatment. Better vaccination, sanitation, medical care and access to health services can lower the risk that people die from preventable or treatable conditions. A is wrong because migration does not automatically reduce deaths and is not the basic reason for improved survival. C is wrong because a change in the meaning of birth rate has no direct connection with mortality. D is wrong because an increase in physical area does not itself make people healthier or reduce deaths. The actual change in death rate also depends on age structure and other conditions, but improved prevention and treatment are the central explanation here. Memory cue: prevention plus treatment can lower mortality.

Correct answer: A. Natural increase and in-migration

Direct answer: A. Urbanisation means that the urban population grows in size or becomes a larger share of the total population. Two processes may contribute at the same time. First, natural increase occurs when births exceed deaths among people living in the city. Second, in-migration occurs when people move into the city, often from rural areas or other regions. Together, these can make urban population grow rapidly. B is wrong because death rate alone is not a complete population-growth process and deaths generally reduce population. C is wrong because physical area is not a population-change process. D is wrong because out-migration removes people from the city, although it may occur alongside growth in some circumstances. The exact balance differs by city. Memory cue: urban growth can come from births plus people coming in.

Correct answer: B. Zero effect

Direct answer: B. Net migration is calculated by subtracting out-migration from in-migration: net migration = in-migration − out-migration. If the number entering equals the number leaving, the two amounts cancel each other and net migration is zero. This means migration by itself produces no net addition or loss in the total population, although it may still change the composition or characteristics of the population. A is wrong because there are not more arrivals than departures. C is wrong because departures do not exceed arrivals. D is wrong because natural increase is a different component, calculated from births minus deaths. Total population can still change if births and deaths are unequal, even when net migration is zero. Memory cue: equal in and out means zero net migration.

Correct answer: A. Because people move within the country

The direct answer is option A. Internal migration means that people move from one place to another within the same country, such as from a village to a city or from one state to another. Step by step, the place of residence changes, so the population of the source area decreases and the population of the destination area increases. However, when both areas are added together, the same people are still inside the country. Hence the national total normally remains unchanged. Option B is wrong because migration is movement, not birth. Option C is wrong because internal migration does not make deaths disappear. Option D is wrong because crossing an international border describes international migration, not internal migration. Internal migration changes distribution and density between places, although births, deaths or later international movement may separately change the national total. Memory cue: internal movement redistributes people; international movement can change a country’s total.

Correct answer: A. When people enter or leave by crossing a national border

The direct answer is option A. International migration occurs when people move across the boundary of one country and another country. A person entering a country is an international in-migrant, while a person leaving it is an international out-migrant. These movements directly affect the country’s total population: arrivals add people and departures remove people. Option B describes a very local move and does not cross a national boundary. Option C concerns the balance of natural change; equal births and deaths would make natural increase zero, but this statement is not international migration. Option D concerns area and has no direct connection with people crossing borders. A useful relationship is: population change = births minus deaths plus in-migration minus out-migration. Memory cue: for national migration effects, look first for a national border.

Correct answer: A. Death rate

The direct answer is option A, death rate. Better health facilities can provide more timely treatment, preventive care, maternal and child care, vaccination and emergency support. These improvements can reduce the number of deaths, so they most directly affect mortality or the death rate. The effect is demographic because deaths are one of the components used to calculate natural increase. Option B is incorrect because hospitals and clinics do not change the physical area of a region. Option C is incorrect because landform refers to natural features such as plains, plateaus or mountains and is not changed directly by health services. Option D is unrelated to the population-change calculation. Better health may also influence life expectancy and population structure over time, but the immediate component in this question is the death rate. Memory cue: improved care mainly reduces preventable deaths.

Correct answer: A. Migration

The direct answer is A: migration. Migration is the movement of people from one place to another. The place people leave is the source area, and the place where they settle is the destination area. If more people leave the source than enter it, its population may fall or its growth may slow. At the same time, the destination receives those people, so its population may rise. B, births, add people to the place where the babies are born but do not by themselves transfer people from a source to a destination. C, deaths, reduce population where they occur but do not increase another area’s population. D, natural increase, is the difference between births and deaths and does not describe movement between places. Migration can be internal, within a country, or international, but the important idea here is movement and its two-sided effect. Memory cue: migration takes people out of one place and brings them into another.

Correct answer: A. The population rises and food demand increases

The direct answer is A. When population increases, more people need food, so total food demand generally rises. Food planning must then consider production, storage, transport, distribution, prices, and access for the larger population. The exact amount of food needed also depends on people’s diets and other conditions, but the basic planning link is clear: more residents create greater aggregate demand. B and C describe situations in which there is no population or no food requirement, so they cannot represent a real increase in food-planning pressure. D concerns a physical change in a mountain and does not directly indicate how many people need food. A is therefore the only option connecting population change with a population requirement. Memory cue: more people usually mean more meals, so population growth must be included in food planning.

Correct answer: A. In-migration and out-migration are equal

The direct answer is A. Net migration measures the balance between people entering and leaving an area. It is calculated as in-migration minus out-migration. If 500 people enter and 500 leave, the calculation is 500 − 500 = 0, so migration itself causes no net gain or loss, even though many people have moved. B describes zero natural increase, because births and deaths are equal; it does not necessarily mean net migration is zero. C compares births with in-migration, which are different population processes and cannot establish the migration balance. D also compares unrelated quantities and does not show that entries and exits are equal. A is correct because the two migration flows exactly cancel each other. Memory cue: net migration = in − out; equal flows give zero.

Correct answer: A. Births are more than deaths

Answer: A, when births are more than deaths. Population change has two main parts: natural change and net migration. Natural change is calculated as births minus deaths. Net migration is in-migration minus out-migration. If net migration is zero, the numbers entering and leaving through migration balance each other. However, the population can still rise if more people are born than die. For example, 1,000 births and 700 deaths produce a natural increase of 300; adding zero net migration still gives a total increase of 300. Option A is correct because births add people and deaths remove people, leaving a positive balance. Option B would produce a natural decrease. Option C would produce no natural change, so with zero net migration the total change would be zero. Option D is not a condition for increase and cannot describe a growing population. Memory cue: total change = (births − deaths) + (in-migration − out-migration).

Correct answer: A. Internal migration occurs within one country, whereas international migration crosses a national border

Answer: A. Migration means a person or group changes its usual place of residence. Internal migration takes place within the boundaries of the same country. A person may move from one village to another, from a village to a city, or from one state to another, and the movement is still internal because no national boundary is crossed. International migration takes place when a person moves from one country to another and crosses a national boundary. Option A states this legal and geographical distinction accurately. Option B is wrong because internal migration can occur in many directions, not only from rural areas to cities, and international migration is not limited to cities. Option C is wrong because either type may be temporary or permanent. Option D reverses the idea: movement across a state boundary within one country is internal, while movement across a national boundary is international. Memory cue: state or district boundary can still be internal; country boundary means international.

Correct answer: A. When both are high and deaths and out-migration are low

Answer: A. Births and in-migration are processes that add people to a population. If both are high, many people are added through natural increase and through movement into the area. For growth to be rapid, the processes that remove people should not cancel these additions; therefore deaths and out-migration should be low. In symbols, total change is (births − deaths) + (in-migration − out-migration). High births and high in-migration make the positive terms large, while low deaths and low out-migration keep the negative terms small. Option A includes all these conditions. Option B would reduce population because deaths and departures are high. Option C removes one important source of addition, so it cannot describe the strongest combined growth. Option D removes births, another major source of increase. The word “together” is important: the question asks about the combined effect of two adding processes, not just one. Memory cue: additions high plus removals low equals rapid growth.

Correct answer: A. When both are high and births and in-migration are low

Answer: A. Deaths and out-migration remove people from an area. If both are high, the population loses people through natural decrease and through movement to other places. A rapid decline occurs when the processes adding people—births and in-migration—are low, because they cannot compensate for the losses. The formula makes this clear: total change = (births − deaths) + (in-migration − out-migration). High deaths and high out-migration create large negative terms, while low births and low in-migration create only small positive terms. Option A gives the complete condition. Option B would normally support population growth, not decline. Option C removes one of the reducing processes and therefore cannot describe the strongest decline. Option D similarly removes the effect of out-migration. Remember that a population may decline even if some births occur, provided deaths and departures are greater than the additions.

Correct answer: A. When many young agricultural workers move out

Direct answer: A. Agricultural work needs available workers for ploughing, sowing, weeding, harvesting, and other tasks. The source area is the place from which people leave. If many young and employable workers migrate out, fewer people remain to work on farms. This may create a labour shortage, increase the cost of hiring workers, delay farm operations, or make families depend more on older people and women. The key is to connect out-migration with the loss of working-age labour in the place of origin. A is correct because it directly describes this situation. B is wrong because if nobody leaves, migration does not remove farm workers. C refers to people entering an area; it may affect the destination, not necessarily reduce labour in the source area. D concerns deaths, not the movement of agricultural workers. Memory cue: out-migration can mean labour out of the source area.

Correct answer: B. When migration is mainly of one sex

Direct answer: B. Sex ratio describes the balance between females and males in a population. Migration changes this balance when the people moving are mainly male or mainly female. For example, if many men leave an area for employment while women remain, the area may show relatively more females. If mostly women move into or out of an area, the opposite pattern may occur. A is not the best answer because equal movement of males and females generally does not create a major sex-ratio difference through migration. C is wrong because without migration there is no migration-related change in the ratio. D concerns births and deaths, which can affect population change but does not describe the migration condition asked here. The important idea is selective migration: the composition of movers matters, not merely their number. Memory cue: one-sex migration can change the male-female balance.

Correct answer: A. When many people come for seasonal work for a few months

Direct answer: A. Temporary migration means that people move for a limited period and later return or move elsewhere. Even though these migrants do not stay permanently, planners must count them while they are present. A large seasonal workforce may need temporary housing, drinking water, sanitation, transport, health care, safety arrangements, and sometimes schools or food services. If planning considers only the permanent population, these temporary needs may be missed. A is correct because many people arriving for several months can sharply increase local demand during that period. B is wrong because no arrival creates no temporary migrant demand. C may affect population change, but it does not by itself describe temporary migration. D does not explain why planning would need to consider temporary migrants. The important distinction is duration: short-term movement can still have real short-term effects. Memory cue: temporary people still require permanent-quality planning while they are present.

Correct answer: A. When people move for education, marriage, safety, or family reasons

Direct answer: A. Migration is often linked with employment, wages, and livelihood, so it can be an economic process. However, people also move for social reasons. Education may take a student to another town, marriage may lead to a change of residence, safety concerns may force a family to move, and family responsibilities may bring relatives together. These movements involve relationships, customs, security, and access to social opportunities, not only income. A is correct because it lists clear non-economic reasons for changing place. B describes no migration. C refers to physical area and does not describe movement of people. D is a demographic event, not a social reason for migration. The important lesson is that migration has multiple causes; economic and social motives may operate together. Memory cue: migration asks not only “for work?” but also “for whom, what opportunity, and what safety?”