Processes of Population Change

Correct answer: A. Population changes through three basic demographic processes: births, deaths and migration. Births add people to a population, while deaths reduce it. Migration changes population through the movement of people: in-migration adds people to a place and out-migration removes them from that place. A simple way to understand population change is natural increase, which is births minus deaths, together with the effect of migration. B lists weather elements, not demographic processes. C contains economic and physical-resource terms, not the three basic population components. D lists natural hazards, which may affect people but are not themselves the standard processes of population change. This distinction is useful in many questions: ask whether the factor adds people through birth, removes them through death, or changes their location through migration. Memory cue: population change = B-D-M: births, deaths, migration.

Correct answer: B. Natural increase is calculated from births minus deaths, without including migration. Therefore, if deaths are greater than births, the result is negative. For example, if a population has 8 births and 10 deaths during a period, the natural increase is 8 − 10 = −2 per the chosen population unit. B is correct because deaths exceed births. A is wrong because births exceeding deaths produce positive natural increase. C is wrong because equal births and deaths produce zero natural increase, not a negative value. D is wrong because inward migration affects total population change but is not part of natural increase. The broader population change can be expressed as natural increase plus net migration, but the word “natural” limits the calculation to births and deaths. Memory cue: natural increase = births − deaths; a negative answer means deaths are greater.

The direct answer is A. Population means the number of people living in a place, and that number changes through three main demographic processes: births add people, deaths remove people, and migration moves people into or out of the area. In a simple relationship, population change depends on births minus deaths plus net migration. Option B lists elements of weather or climate, which may influence living conditions but are not population-change processes. Option C lists physical landforms. Option D lists natural resources or materials. None of those lists directly counts the demographic additions, removals, and movements that change population. Memory cue: remember B-D-M—births, deaths, migration.

The direct answer is B: births increase population. Population is the total number of people living in a place. When a baby is born, one new person is added to that population, so the number rises if deaths and migration are not being considered at the same moment. Births are therefore an adding process in demographic change. Option A is wrong because births do not remove people; deaths or movement out of the area can reduce the number. Option B is correct because a new member enters the population. Option C is wrong because birth does not change the physical area of a region. Option D is wrong because rivers are natural water features and are not created by human births. Memory cue: birth means add one; death means subtract one.

The direct answer is C. When a person dies, that person is no longer counted among the living residents of the area, so deaths reduce population size. Population growth is affected by the balance between additions such as births and in-migration and reductions such as deaths and out-migration. Option A is wrong because death removes a person rather than doubling the population. Option B is wrong because each death changes the number of living people, even though births or migration may offset the change in a larger calculation. Option D is wrong because death itself is not migration; migration means moving from one place to another. Memory cue: births and arrivals add, while deaths and departures subtract.

The direct answer is B. In-migration means people entering a particular area from another place with the intention of living there, temporarily or permanently depending on the context. These newcomers add to the receiving area’s population. Option A describes out-migration, because people are leaving an area. Option B is correct because the prefix “in” helps us remember movement into a place. Option C is a change caused by births, not migration; a baby born in the area is not automatically an in-migrant. Option D concerns mortality and does not describe movement at all. Memory cue: in means inward or coming in; out means leaving out.

The direct answer is C. Out-migration is the movement of people away from their present area to another place. For the area being left, this movement can reduce population, although the people may add to the population of the place where they settle. Option A is the opposite process, called in-migration. Option B concerns births, which add people naturally but do not involve movement between places. Option C is correct because “out” signals movement away from an area. Option D concerns mortality conditions and does not describe movement. Memory cue: in-migration comes in; out-migration goes out. Always identify the area being discussed before deciding whether movement is in or out.

Direct answer: Option A, births and deaths. Natural increase means the change in population produced by the difference between the number of births and the number of deaths in a place during a period. It does not include people moving into or out of the place. Step by step: a birth adds one person to the population, while a death removes one person. Therefore, natural increase is calculated as births minus deaths. If births are greater than deaths, the natural increase is positive; if deaths are greater, there may be a natural decrease. Option A is correct because it names both processes used in this calculation. Option B is wrong because in-migration and out-migration describe movement and together show net migration, not natural increase. Option C is wrong because rainfall and temperature are climate elements. Option D is wrong because soil and minerals are natural resources, not population processes. Memory cue: natural increase comes from natural events—births and deaths; movement between places is migration.

Direct answer: Option B, the population will increase. To understand this, compare the two processes: births add people to a population, while deaths remove people. When the number of births is greater than the number of deaths, the difference is positive. This positive difference is called positive natural increase, so the population rises, provided the question is considering these two processes. Option A is wrong because a decrease would occur when deaths were greater than births, or when other population factors produced a net loss. Option B is correct because more additions than removals result in growth. Option C is wrong because having more births than deaths cannot make the entire population zero; it indicates an increase. Option D is wrong because population change does not automatically change the physical area of a region. Memory cue: more births than deaths means more people added than removed, so think “natural increase.”

Direct answer: Option C, natural decrease can occur. A population changes naturally through births and deaths. Births add people, and deaths remove people. If deaths are more numerous than births during a period, the calculation births minus deaths gives a negative result. This negative natural change is called natural decrease. Option A is wrong because rapid growth would require births to exceed deaths, not the reverse. Option B is wrong because the population is not necessarily stable; a greater number of deaths makes a decrease possible. Option C is correct because it accurately describes the result of deaths exceeding births. Option D is wrong because migration is a separate process, and the information given does not prove that people will move into the area. A place could have natural decrease while migration changes the final population in either direction. Memory cue: births are additions and deaths are subtractions; when subtractions are larger, natural change becomes negative.

Direct answer: Option A, in-migration. In-migration occurs when people enter a particular area from another place to live there. These newcomers are added to the population of the area they enter, so in-migration can increase its population. Option A is correct because it directly describes people coming into the area. Option B is wrong because out-migration means people leave an area, which can reduce its local population. Option C is wrong because deaths remove people from the population rather than bring new residents. Option D is wrong because drought is an environmental condition; it may influence movement, but it is not the population process named in the question. Notice that the question asks about people coming from outside, so focus on the direction of movement. Memory cue: “in” means entering; in-migration brings people in. The final population also depends on births, deaths, and people leaving, but the process asked here is specifically in-migration.

Direct answer: Option B, out-migration. Out-migration occurs when people leave a particular area to live in another place. Their departure removes them from the population of the original area, so out-migration can reduce that area's population. Option A is wrong because births add people to the local population. Option B is correct because it names the movement away from the area described in the question. Option C is wrong because in-migration means people enter the area and can increase its population. Option D is wrong because rainfall is a physical element of climate, not a process in which people leave. The word “out” is the key clue: it indicates movement away from the place being studied. The final population may also be affected by births, deaths, and arrivals, but the specific process of people leaving is out-migration.

Direct answer: Option A, births occurring during a period. Birth rate is a demographic measure that describes the occurrence of births in a population during a specified period, commonly expressed as the number of live births per 1,000 people in one year. The exact rate uses both the number of births and the size of the population, but the central idea is births. Option A is correct because it identifies the population event measured by birth rate. Option B is wrong because height is a physical characteristic of land, not a measure of births. Option C is wrong because river width is a feature of drainage and does not define birth rate. Option D is wrong because soil colour is a soil characteristic. Do not confuse birth rate with natural increase: birth rate concerns births, whereas natural increase compares births with deaths. Memory cue: the first word gives the clue—birth rate measures births in a population during a period.

Direct answer: Option A. Death rate is the number of deaths in a population during a specified period, commonly stated as deaths per 1,000 people in one year. The phrase “per 1,000 population” makes comparison between places or periods easier even when their total populations differ. Option A is correct because it gives both the event—deaths—and the usual population basis—1,000 people in a year. Option B describes birth rate because it counts live births. Option C describes in-migration, the movement of people into an area. Option D describes out-migration, the movement of people away from an area. Remember that death rate is not the same as total deaths: a rate relates deaths to population size and time. Memory cue: death rate = deaths per 1,000 population per year.

Direct answer: Option B, people entering and leaving. Net migration measures the difference between in-migration and out-migration during a period. In-migration adds people to the area, while out-migration removes people from it. In simple form, net migration = people entering minus people leaving. If more people enter than leave, net migration is positive; if more leave than enter, it is negative; if the numbers are equal, net migration is zero. Option A is wrong because the difference between births and deaths describes natural increase or natural decrease. Option B is correct because it names the two flows used for net migration. Option C is wrong because rainfall and temperature are climate elements. Option D is wrong because a river and a lake are physical water features, not population movements. Memory cue: migration means movement, and “net” means the balance between inward and outward movement.

Direct answer: Option A, when entrants are more than leavers. Net migration is calculated by subtracting the number of people leaving from the number entering: net migration = in-migration − out-migration. If 500 people enter and 300 leave, the balance is +200, so net migration is positive. Option A is correct because more people are added through movement than removed. Option B is wrong because more leavers would produce a negative net migration. Option C concerns births and deaths, which determine natural change rather than net migration. It may affect total population change, but it does not define the migration balance. Option D is wrong because the statement does not describe a positive difference between entrants and leavers; moreover, if nobody lives there, there are no stated entrants. Positive net migration can raise the local population, although the final population also depends on births and deaths. Memory cue: positive net migration means the inward flow is larger than the outward flow.

Direct answer: Option B, when leavers are more than entrants. Net migration is found by subtracting out-migration from in-migration. When the number of people leaving an area is greater than the number entering it, the result is negative. For example, if 400 people leave and 250 enter, net migration is 250 − 400 = −150. Option A is wrong because more entrants produce positive net migration. Option B is correct because the outward movement is larger than the inward movement. Option C is about births and does not by itself determine net migration; births belong to natural change. Option D is also about deaths and natural change, not migration. Negative net migration can contribute to a decline in the area's population, although births and deaths must also be considered for the total change. Memory cue: a negative migration balance means the exit flow is bigger than the entry flow.

Direct answer: A, 20. Net migration measures the balance between people entering and people leaving an area. People entering are called in-migrants, while people leaving are called out-migrants. The formula is: net migration = in-migration − out-migration. Here, 50 people enter and 30 leave, so 50 − 30 = 20. Therefore, migration produces a net increase of 20 people in the area. A is correct because it uses the correct order and calculation. B, −20, would be correct only if 30 people entered and 50 left, so that leaving exceeded entering. C, 30, is merely the number of people who left; it does not show the balance. D, 80, incorrectly adds the two numbers, although net migration requires subtraction. Memory cue: in minus out.

Direct answer: B, negative 30. Use the formula net migration = people entering − people leaving. Thus, net migration = 40 − 70 = −30. The negative sign shows that 30 more people left the area than entered it, so the area experienced a net loss through migration. A, positive 30, reverses the subtraction and would apply if 70 entered and 40 left. B is correct because the result is −30. C, zero, would require equal numbers entering and leaving, such as 40 and 40. D, positive 110, comes from adding 40 and 70 and also gives the wrong sign; addition does not measure net migration. Common confusion: a negative result does not mean that a person is negative; it indicates a decrease in population caused by migration.

Direct answer: A. Population change is determined by three demographic processes: births, deaths and migration. Births add people, deaths remove people, and net migration represents the balance between people entering and leaving. In simple form, population change = births − deaths + net migration. A is correct because it includes all three components. B is wrong because rivers, mountains and soil are physical features or environmental elements, not direct demographic components. C describes weather-related elements and does not calculate population change. D lists parts of the natural world and wildlife, which are not population-change components for human population. A useful memory cue is B-D-M: births, deaths, migration. Do not confuse natural increase, which is births minus deaths only, with total population change, which also includes net migration.

Direct answer: A. To find total population change, begin with the number of births because births add people. Subtract deaths because deaths reduce the population. Then add net migration, which may be positive when more people enter or negative when more people leave. Therefore, the correct formula is change = births − deaths + net migration. A is the only option that contains all three demographic processes in the correct relationship. B combines rainfall and soil, which are environmental factors and cannot calculate human population change. C compares a river with a mountain, which has no demographic meaning. D is an unrelated multiplication expression. Remember that natural increase is only births − deaths; adding net migration gives total population change.

Direct answer: A, 50. Natural increase means the change caused only by births and deaths, without considering migration. The formula is natural increase = births − deaths. Substituting the given values gives 200 − 150 = 50. Thus, births exceed deaths by 50, so the population has a natural increase of 50 people. A is correct. B is only the number of deaths, not the difference between births and deaths. C is only the number of births and ignores deaths. D is the sum of births and deaths; adding them does not show increase because deaths reduce population rather than add to it. A safe memory cue is “born minus gone by death.” If migration were also given, it would be considered separately for total population change, but it is not part of this natural-increase calculation.

Direct answer: C, zero. Natural increase is calculated as births − deaths. Here the calculation is 300 − 300 = 0. The number of people added through births exactly equals the number removed through deaths, so there is no natural increase or natural decrease. C is correct because equal values balance each other. A, very high, is wrong because the difference is not large; it is zero. B, negative, would occur when deaths are greater than births, such as 300 births and 350 deaths. D, unknown, is wrong because both required numbers are supplied and the result can be calculated. Migration could still change the total population, but no migration information is given and it is not needed for natural increase. Memory cue: equal births and deaths mean a balanced natural change of zero.

Direct answer: B, a decrease of 60. Natural change is found by subtracting deaths from births: 100 − 160 = −60. The negative result means deaths are greater than births by 60, so the population experiences a natural decrease of 60 people. B states this meaning correctly. A, an increase of 60, reverses the sign and would be correct if births exceeded deaths by 60. C, an increase of 260, adds the two figures and ignores that deaths reduce population. D, zero, would require births and deaths to be equal. This calculation concerns natural change only; migration could alter total population separately. Common-confusion warning: a negative numerical result should be expressed as a decrease, not as a positive increase.

Direct answer: A. Migration is the movement of people from one place to another. People may leave a village when suitable jobs, colleges, hospitals or other services are limited, and they may be attracted to cities by employment, education and facilities. These attractions are called pull factors because they draw people toward a destination. A is correct because jobs and education are realistic reasons for village-to-city migration. B is wrong: stopping a river is not a normal demographic reason for moving to a city. C is unrelated because changing a soil name does not create a reason to migrate. D is also unrelated; removing mountains is not a usual purpose of village-to-city movement. Village-to-city migration can involve both push factors at the village and pull factors at the city, but the option asks for a valid reason, which A provides.