Population Growth

Correct answer: A. Younger age groups may become larger

Child mortality is the death of children at young ages. When it falls rapidly, more children survive. If the birth rate does not decline immediately, many children continue to be born and a larger share of them remains alive. This can enlarge the child and adolescent age groups in the medium term. Therefore, the correct choice is A.

The effect is on the composition of the population, not merely its total size. For example, the same number of births produces a larger surviving cohort when fewer children die. The elderly group will not immediately become dominant, because the immediate change concerns survival among children. Later, these larger young cohorts may enter working and reproductive ages, producing further demographic effects. Option C reverses the likely direction, while D ignores improved survival.

Correct answer: A. Much of the growth came from young adult or working-age migration

The total population and the child population do not have to grow at the same rate. If a city receives many young adults for employment, education or other opportunities, the working-age group can expand rapidly. These newcomers increase the total population, but they are not counted in the 0–14 age group.

Thus, a 30 percent total increase alongside only a 4 percent increase among children is most plausibly explained by young adult or working-age in-migration. Option A is correct. A very high birth rate would normally raise the child group more strongly, while saying that children grew by 30 percent contradicts the given figure. The pattern does not make the total data impossible.

Correct answer: A. Large inflows and outflows are nearly offsetting each other

Gross migration measures the total size of movement, considering both people entering and people leaving. Net migration measures only the difference between those two flows. Therefore, a high gross figure can coexist with a small net figure when large inflows and outflows are nearly equal.

If many people enter but almost as many leave, the remaining balance may be only 1000. For instance, 101000 arrivals and 100000 departures produce a net migration of 1000, while the total movement is very large. Thus, option A is correct. A net figure of 1000 does not mean that only 1000 people moved or that out-migration was zero.

Correct answer: C. 900000

A simple one-year increase is calculated by applying the percentage growth rate to the starting population. The rate 0.45 percent must be written as a decimal, \(0.45/100 = 0.0045\). Multiplying this fraction by the population gives the number added during one year.

The increase is \(200000000 \times 0.0045 = 900000\). Therefore, approximately 900000 people, or 9 lakh people, are added in one year. Option C is correct. The percentage looks small, but it is applied to a very large base population, so the resulting number is substantial.

Correct answer: A. The working-age share may increase

Zero net migration means that the total number of people entering the city equals the total number leaving it. However, equal numbers do not imply equal age groups. If arrivals are mainly young adults aged 20 to 29 and departures are mainly people above 60, the age composition changes even though the total population effect of migration is zero. The working-age share may therefore increase, so option A is correct.

The statement says “may increase” because the final result also depends on the city’s existing age structure and the exact numbers involved. It does not prove that the total population will double, nor that the elderly share must increase. Thus numerical balance in migration can coexist with a significant structural effect. Age-selective migration changes the composition, not necessarily the total size.

Correct answer: A. An ageing but still growing population

A decline in birth rates usually reduces the proportion of children and gradually raises the average age. Yet the total population can continue to rise for some time because large earlier age groups may still be entering adulthood and having children. Low mortality and positive migration can also contribute to continued growth. Thus ageing and growth can occur together.

The combined pattern is an ageing but still growing population, so option A is correct. Complete stability would mean no overall increase, which contradicts the statement. High fertility and rejuvenation contradict falling birth rates, while migration-driven decline is not supported because the total population is rising rather than declining.

Correct answer: A. Low or moderate

Natural increase is determined by the difference between the birth rate and the death rate. A high birth rate alone does not guarantee rapid growth. If the death rate is also high and nearly equal to the birth rate, the difference between them is small. Consequently, the natural increase may be low or moderate, even though both rates individually are high.

For example, if the birth rate is 40 per thousand and the death rate is 38 per thousand, the natural increase is only 2 per thousand. It is not necessarily extremely high, and it is not always negative. Therefore option A is correct. The supplied explanation correctly focuses on the gap between the two rates rather than on the birth rate alone.

Correct answer: A. The gap will widen and natural increase will accelerate

Natural increase is determined by the gap between the birth rate and the death rate. If the death rate falls rapidly while the birth rate stays high, fewer people are being lost and many people continue to be added. Consequently, the difference between births and deaths becomes larger, so natural increase accelerates. Therefore, option A is correct.

For example, if the birth rate remains 30 per thousand and the death rate falls from 20 to 10 per thousand, the gap increases from 10 to 20 per thousand. The birth rate has not risen, but the lower death rate still makes the net natural increase greater. The gap does not have to become zero; it widens as long as births remain substantially above deaths. Thus, option A best describes the change.

Correct answer: A. Their age structures and demographic turnover differ

Zero total growth only describes the final balance of population changes; it does not show that births, deaths, and age groups are identical. A country with high birth and death rates has considerable demographic turnover. It may have many young people entering the population and many deaths leaving it. Another country with low birth and death rates may change more slowly and have a different age distribution, often with a larger relative share of older people.

Thus option A is correct: their age structures and demographic turnover can differ. Equal total growth can result from very different internal flows. Zero growth does not make the countries identical, and births and deaths are closely related to age structure. Land area alone cannot explain the demographic difference. Migration may also affect the exact balance, but it does not remove the main conclusion.

Correct answer: C. More than 35 years

The Rule of 70 estimates doubling time by assuming that the annual growth rate stays constant. A result of 35 years is therefore based on a fixed rate throughout those 35 years. If the actual rate falls every decade, the population does not continue growing at the original speed.

Because growth becomes slower, the population will need longer than the constant-rate estimate to double. Thus the real doubling time will likely be more than 35 years, making option C correct. It may even fail to double within the initially estimated period, depending on how sharply the rate declines. It cannot reasonably be less than 35 years under the stated falling-rate condition.

Correct answer: A. School demand may remain high while labor force and future births weaken

Births and migration affect different parts of a population structure. Many births increase the number of children, so schools may continue to face high demand. At the same time, heavy out-migration of people aged 18 to 35 removes many working-age adults from the rural area. It may also remove people who would otherwise become parents locally.

Thus the region can simultaneously have strong school demand because of earlier or current births and a weaker local labor force because young adults leave. Future births may also weaken if fewer potential parents remain. The result is not guaranteed in every case, but it is a plausible combined effect. Therefore option A is correct; the other choices use absolute claims or ignore age-selective migration.

Correct answer: C. 0 percent

Total growth is the algebraic sum of natural increase and net migration. A positive natural increase adds population through births exceeding deaths. Net out-migration removes population, so it is represented by a negative rate. Equal positive and negative rates cancel each other when added.

The calculation is \(1.6+(-1.6)=0\) percent. Therefore, the total population has zero net growth, making option C correct. This does not mean that no births, deaths, or migration occur; it means their combined effect leaves the population numerically unchanged over the stated period. Adding the two magnitudes as 3.2 percent would ignore the negative sign of out-migration.

Correct answer: A. Pressure on labor force and tax base with higher pension and health demand

A stable total population can hide major changes in age structure. If the number and share of people over 65 rise while the working-age population shrinks, fewer workers may be available to produce goods and services and to pay taxes. At the same time, more people may need pensions, health care, and long-term support. The resulting dependency pressure can affect public budgets and economic growth.

Therefore option A is the most important likely effect. Stable total population does not make age structure irrelevant; the distribution by age strongly influences labor supply and public spending. School demand would not necessarily double because the older group is increasing. Economic problems will not all disappear, and the described changes do not automatically mean every economic indicator worsens, but pressure on labor, taxes, pensions, and health services is a logical concern.

Correct answer: B. It will decrease

Per-person food availability depends on total food divided by total population. If population grows faster than food production, the numerator increases less than the denominator. Assuming food distribution, imports, storage, and other conditions do not offset this difference, less food will be available for each person on average.

For illustration, take initial population and food as 100 units each. After the changes, population is 109 and food is 106. Per-person availability changes from \(100/100=1\) to \(106/109\), which is less than 1. Therefore, per-capita food availability decreases, so option B is correct.

Correct answer: A. Pressure on per-capita water capacity will increase

Per-person water capacity is found by dividing total supply capacity by population. Here, population grows much faster than supply capacity: 14 percent compared with only 4 percent. Thus the available capacity is being shared among relatively more people, so the capacity available to each person falls and pressure on the system rises.

For example, if initial capacity and population are both 100 units, the new values are 104 capacity units and 114 population units. Per-person capacity changes from \(100/100=1\) to \(104/114\), which is lower. Therefore, pressure on per-capita water capacity increases, making option A correct. This does not necessarily prove an immediate physical shortage, but it indicates greater pressure.

Correct answer: A. Large cohorts born earlier are still entering working ages

A country's current growth rate describes recent births, deaths, and migration, but age structure changes more slowly. The working-age population in the next 15 years includes people who were born many years earlier. If a large group was born during a period of higher fertility, that group will gradually enter working ages even while the present growth rate is declining.

This is a cohort effect and can continue the growth of the working-age population for some time. A falling total growth rate does not make every age group shrink immediately, because population groups move through the age structure over time. Therefore option A is correct. The explanation does not require migration to be zero and is directly connected to the country's earlier birth history.

Correct answer: A. By jointly examining births, deaths, migration, age structure, absolute growth, growth rates, cohort change, and time series

Expert analysis treats population growth as a multi-dimensional process rather than a single number. Births and deaths show natural change, migration changes both size and composition, and age structure indicates future demographic momentum. Absolute growth tells how many people were added, while the growth rate permits comparison between populations of different sizes. Cohort change and time series reveal how groups evolve and whether a pattern is temporary or persistent. Thus option A is the most complete approach.

Total population alone cannot explain why change occurred, and one rate can hide important differences in age, migration, or timing. A strong analysis combines the listed components and interprets their interaction across years. For example, a young age structure may support future growth even after fertility declines, while out-migration can reduce working-age groups. Therefore, the comprehensive set in option A is required.

Correct answer: A. Increase of 2300

Total population change has two components: natural increase and net migration. Natural increase is births minus deaths, so it is \(9600-6400=3200\). Net migration is in-migrants minus out-migrants, giving \(1800-2700=-900\). The negative result means migration reduced the population by 900.

Combining the components gives \(3200+(-900)=2300\). Thus the region experienced an increase of 2300 people, so option A is correct. The figure 3200 counts only births and deaths and ignores outward migration. The other options do not match the combined demographic balance.

Correct answer: A. 17 per thousand

The natural growth rate is calculated by subtracting the death rate from the birth rate. Here it is \(34-12=22\) per thousand. Net migration must then be included. A net migration rate of \(-5\) per thousand means that out-migration exceeds in-migration by 5 people per thousand, so it reduces total growth.

Therefore, total growth rate is \(22+(-5)=17\) per thousand. Option A is correct. The value 22 per thousand is only the natural increase and would be the answer if migration were zero. The negative sign must not be ignored, because it represents a loss through migration.

Correct answer: B. -0.7 percent

Total population growth can be separated into natural increase and net migration. In rate form, the relationship is \(\text{total growth rate}=\text{natural increase rate}+\text{net migration rate}\). Therefore, to find net migration, subtract the natural increase rate from the total growth rate.

Here, \(\text{net migration rate}=1.4-2.1=-0.7\) percent. The negative sign is essential: it means more people are leaving the country than entering it, or that out-migration exceeds in-migration by 0.7 percentage points. Hence option B is correct. A positive value would mean net in-migration, which is not supported by these figures.

Correct answer: A. Decrease of 0.2 million

Total population change is calculated by adding natural increase to net migration. Natural increase equals births minus deaths: \(2.5-1.4=1.1\) million. Net out-migration of 1.3 million is a loss, so it must be subtracted from the natural increase. The total change is therefore \(1.1-1.3=-0.2\) million.

A negative result means that the population decreases rather than increases. The decrease is 0.2 million, which is 2 lakh people. Hence option A is correct. The 1.1 million figure is only the natural increase before migration is considered, while 1.3 million is the migration loss alone. Both components must be included to find the total population change.

Correct answer: B. 1020000

To calculate a one-year increase, multiply the population by the growth rate written as a decimal. A population of 120 million is 120,000,000 people, and 0.85 percent is \(0.85\div100=0.0085\). Thus the increase is \(120000000\times0.0085=1020000\). The correct choice is B, 1,020,000 people, or about 1.02 million.

This is a simple one-year estimate. It applies the stated rate to the starting population and does not include compounding or changes during the year. Although 0.85 percent looks small, it is applied to a very large base. Option A is too low, while 1.2 million would correspond to a 1 percent increase in 120 million. The units are people, so the result represents additional population, not a percentage.

Correct answer: B. Final population is 145 percent of initial population

A 45% increase over fifteen years means the final population is the original population plus 45% of it. Therefore the final population equals 145% of the initial population, or 1.45 times the initial value. Option B is definitely correct. The statement gives a total change, not the pattern of change during each individual year.

The population may have grown at different rates in different years, so an exact annual increase of 3% cannot be inferred. Also, the total change could result from births, deaths, and migration together; it does not establish a particular birth rate or zero migration. Thus options A, C, and D make claims unsupported by the information. Only option B follows directly from the percentage definition.

Correct answer: A. A small rate on a large population base can still add many people

A growth rate is a percentage of the existing population, whereas absolute increase is the actual number added. These measures can move differently when the population base is large. Even 0.9 percent of a very large population may be many people. Therefore a declining rate does not automatically mean that the annual number added is small or that it has fallen below the previous number.

For instance, 0.9 percent of 100 million is 900000 people. The exact figures in the question are not supplied, but the principle is clear: a large base multiplied by a smaller rate can still produce a large absolute increase. Thus option A is the most appropriate answer. Zero deaths, a definitely higher birth rate, or a doubled land area is neither stated nor necessary to explain the result.

Correct answer: A. Demographic momentum caused by a youthful age structure

Replacement-level fertility does not immediately produce a stable population because population structure reflects earlier fertility patterns. If previous decades had high fertility, a large group of young people may now be entering or moving through reproductive ages. Even when each woman has nearly replacement-level fertility, the total number of mothers can remain large.

Consequently, births may continue to exceed deaths for several decades. This continuing population increase is called demographic momentum and is linked to a youthful age structure. The result is not guaranteed by zero deaths, expanding land, or always-positive migration. Therefore option A is correct under the stated conditions.