Population Growth

Natural increase is found from the difference between the birth rate and the death rate. A high birth rate by itself does not guarantee a high natural increase, because many deaths may occur at the same time. What matters is the size of the gap between the two rates.

If both rates are very high but close to each other, their difference is small. Consequently, the population may show only limited natural increase. Therefore, option A is correct. Option B ignores the death rate, option C is too strong because the result need not be negative, and option D incorrectly claims that births alone determine natural increase. Migration is not part of this calculation.

Natural increase is determined by the difference between the birth rate and the death rate; migration is separate. When the death rate falls sharply but the birth rate remains high for several years, many fewer people die while births continue at roughly the earlier level. The gap between births and deaths therefore becomes large and positive.

This situation is typical of the early part of demographic transition. Improved sanitation, nutrition, and medical care can reduce mortality before families begin to prefer smaller numbers of children. As a result, population grows rapidly through natural increase during the interval. Option A is correct. Zero or negative growth would require births not to exceed deaths, and migration is not needed to explain this change.

Zero total growth means that additions to the population are balanced by losses, but it does not mean that birth and death rates must be equally high or that the age structure must match. A country with births and deaths near 30 per thousand has much more demographic turnover: many people are born and many die each year. A country with both rates near 8 per thousand has much less turnover.

The first country may have a relatively young population because high birth rates continually add children, even though mortality is also high. The second may have an older or more stable age structure. Thus option A is the valid possibility. Option B is too definite, while C and D do not follow from the given rates.

The Rule of 70 is a quick estimate for doubling time. It uses the formula \(T \approx 70/r\), where \(T\) is the doubling time in years and \(r\) is a roughly constant annual growth rate in percent. The estimate of 44 years assumes that the rate used in the calculation continues without an important change throughout the period.

If the growth rate continually declines, each later year adds fewer people than the constant-rate estimate expects. Population growth therefore becomes slower over time, so reaching twice the original population takes longer than 44 years. The actual doubling time is consequently more than 44 years, making option C correct. It would be exactly 44 years only if the relevant rate stayed approximately constant; a declining rate does not support that assumption.

Migrants aged 19 to 29 are usually entering higher education, training, or the labour market. They often need a place to rent, a reliable way to travel, and opportunities for study or employment. Their arrival can therefore create quick pressure on rental housing, jobs, public transport, and related services. The exact demand may differ between cities, but these needs are much more immediate than services designed mainly for retired people.

Choice A is correct because it combines the main short-term requirements of a young migrant population: rental housing, employment, and transport. Choices B and C focus only on elderly care or pensions, which are not the dominant needs of people in this age group. Choice D is also unsuitable because urban young migrants generally increase demand for services and housing rather than directly creating a need for agricultural land. The question asks for the particularly likely near-term demand.

Births affect the number of children in the present, while migration of adults affects the population structure that will exist later. People aged 20 to 39 are commonly part of the working-age population and may also become parents. If many of them leave, the region loses workers and a substantial part of its future childbearing population, even if births are currently numerous.

Consequently, schools may still face strong demand in the near term because the existing child population is large. Over time, however, the smaller working-age group can weaken the labor force, reduce the number of potential parents, and possibly lower future births. Therefore, option A is the best conclusion. The other choices use absolute claims such as “always” or “necessarily,” which cannot be justified from the information given.

Total population growth combines natural increase with net migration. Natural increase measures the excess of births over deaths, while net migration measures arrivals minus departures. A positive value raises the population and a negative value lowers it. The two effects must therefore be added with their signs, rather than compared only by their absolute sizes.

The calculation is \(+1.8\% + (-1.8\%) = 0\%\). The increase produced by births exceeding deaths is exactly cancelled by the reduction caused by net out-migration. Thus the total population does not change through these two components during the stated period, and option C is correct. This does not mean births equal deaths; it means the two opposite population effects balance each other.

A population can be nearly stable in total size while its internal age structure changes substantially. When the elderly share rises and the working-age group shrinks, fewer workers may be available relative to the number of people needing support. Older people may also require more pensions, medical services, and long-term care. These changes can increase the dependency ratio and place pressure on government budgets, even without rapid total population growth.

The likely result is therefore higher economic and public-finance pressure, so option A is correct. A stable total population does not make age structure irrelevant. School demand would not definitely double, because that depends on births and the size of the child population, not simply on elderly growth. Economic pressure also does not disappear automatically; it may become more serious as the tax base and labour supply narrow.

Per-person food availability depends on the amount of food divided among the total population. If food production grows faster than population, there is more food available, on average, for each person, assuming other conditions do not change. Here, production rises by 10 percent, while population rises by only 6 percent.

For example, imagine an initial population of 100 people and food production of 100 units. After the changes, the population becomes 106 and production becomes 110 units. Food per person changes from 1 unit to about 1.038 units, so it increases by roughly 3.8 percent. Therefore, option B is correct. Unequal distribution or wastage could affect actual access, but those factors are excluded by the question.

Transport capacity and transport demand do not grow at the same rate in this situation. If the population, and therefore the possible number of passengers, rises by 11 percent while capacity rises by only 3 percent, more people must use a relatively smaller increase in services. The most likely result is option A: greater pressure per passenger and more crowding.

For example, if a system served 100 passenger-units before, demand may become about 111, while capacity becomes only 103 units. The gap between demand and capacity grows, so queues, waiting time, overcrowding, and pressure on vehicles or stations may increase. The result is not mathematically inevitable in every city, because travel behavior and new routes may also change, but it is the most reasonable direct inference. The other choices either reverse the likely effect or deny the relationship.

A falling total growth rate describes the current balance of births, deaths, and migration, but it does not immediately change the size of every age group. The people who will be aged 20 to 59 during the next decade were mostly born many years earlier. Their numbers therefore depend strongly on the size of earlier birth cohorts and on survival, not only on today's growth rate.

If large groups were born in the past, those cohorts will continue moving into the 20–59 age range even while newer cohorts become smaller. This is a cohort effect and explains why the working-age group can keep growing after overall growth begins to slow. Thus option A is correct. Option B assumes an instant change in all ages, while C and D contradict basic population accounting.

Population growth cannot be understood from one number alone. It results from natural change, migration, and the age composition of society. Births add people, deaths remove people, and migration can add or remove people. Age structure and cohorts show how many people are likely to enter childbearing or working ages in the future. Absolute increase tells how many people were added, while the growth rate allows comparison between populations of different sizes. A time series shows whether the pattern is temporary or continuing.

Therefore, option A is the most complete and reliable combination. Total population, birth rate, or growth rate alone may describe only one visible part of the process. Combining all the listed measures gives both the causes and the effects of growth and helps experts interpret past trends and estimate future population change. No single indicator can provide this depth of analysis.

Percentage growth compares the increase with the original population, not with the final population. The population rises by 11.4 million, from an initial 60 million. Therefore, the increase is a substantial fraction of the starting population, and the correct choice is 19 percent.

The calculation is: increase = 71.4 - 60 = 11.4 million. Percentage growth = \(\frac{11.4}{60}\times100\) = 19 percent. Thus option C is correct. Dividing by 71.4 would calculate a different proportion and would not represent growth from the original population. The unit, whether millions or crores, cancels in the ratio.

Population change has two parts: natural change and net migration. Natural change is found by subtracting deaths from births. Net migration is found by subtracting out-migrants from in-migrants. A positive final value means growth, while a negative value means decline.

Here, natural increase is \(10400-7100=3300\). Net migration is \(2600-3400=-800\), because 800 more people left than entered. Therefore, total change is \(3300+(-800)=2500\). The region therefore records an increase of 2500, so option A is correct. The value 3300 alone ignores migration.

Total population change has two parts: natural increase and net migration. Natural increase is found by subtracting the death rate from the birth rate. Net migration must then be added, with a negative value reducing the total. Thus, the relevant rates are births, deaths, and people entering or leaving the country.

Here, natural increase is \(31-8=23\) per thousand. Net migration is \(-11\) per thousand, meaning that departures exceed arrivals by 11 per thousand. Therefore, total growth is \(23+(-11)=12\) per thousand. Option B is correct. Option D, 23 per thousand, would ignore migration.

Net migration shows the balance between people entering and leaving a country. It is positive when immigration is greater than emigration and negative when more people leave than enter. Total population growth is made up of natural increase plus net migration, so the two rates must be compared carefully.

Here, total growth is 0.7 percent and natural increase is 1.8 percent. Therefore, net migration is calculated as \(0.7-1.8=-1.1\) percent. The negative sign means that migration reduced the population growth rate; outward migration was greater than inward migration. Thus, option B is correct. Option A reverses the subtraction and gives the wrong sign.

Population change is found by combining natural change with migration. Natural change means births minus deaths. Net out-migration is then subtracted because more people leave the country than enter it. Thus, both the size of the birth–death difference and the migration balance must be considered together.

The natural increase is \(3.0-1.7=1.3\) million, or 13 lakh. Net out-migration removes another 1.5 million, so the total change is \(1.3-1.5=-0.2\) million. The negative sign means a decline, equal to 2 lakh. Therefore, option A is correct. Option C ignores migration and gives only the natural increase.

The percentage tells us what fraction of the starting population is added during one year. A rate of 0.72% means 0.72 persons for every 100 persons, so it must be applied to the full population of 150 million. The result is an increase, not the new total population. This distinction is important because the question asks how many people are added in one year.

Using the simple percentage calculation, increase = \(150000000\times\frac{0.72}{100}\) = \(1080000\). Thus, approximately 1.08 million, or 10.8 lakh, people will be added. Option C is correct. The answer is approximate because it uses a fixed annual rate and ignores changing rates, deaths, and migration during the year.

Percentage growth compares the increase with the original population, not with the final population. The population rises from 37.5 million to 46.5 million, so the increase is 9 million. The base for calculating growth is therefore 37.5 million, because that was the population before the change.

Using the formula, percentage growth is \(\frac{\text{increase}}{\text{original population}}\times100\). Thus, \(\frac{9}{37.5}\times100=24\) percent. Therefore, option C, 24 percent, is correct. A calculation using 46.5 million as the base would give a different figure, but that would not represent growth from the original population.

A percentage increase describes the difference between the starting population and the final population. An increase of 54 percent means that the increase is 54 parts for every 100 parts in the original population. Therefore, the final population contains the original 100 percent plus the additional 54 percent. It is consequently 154 percent of the initial population.

This conclusion does not require the increase to have been equal in every year. The population could have grown quickly in some years and slowly in others. Option A wrongly treats the total percentage divided by eighteen as an exact annual pattern; compound growth would also not be calculated in that simple way. Birth rate and migration are separate demographic facts, so options C and D cannot be inferred from the given information. Thus B is definitely correct.

The percentage growth rate and the absolute number added are related, but they are not the same measure. A percentage is calculated in relation to the population already present. Therefore, a lower percentage can still produce a fairly large addition when the starting population has become much larger. This distinction is essential for interpreting population growth correctly. The other choices make claims that do not follow from the information given: death cannot be assumed to be zero, birth rate need not have increased, and migration may still affect the total.

Let the earlier population be smaller and the later population be much larger. Even if the later rate is only half the earlier rate, applying it to a much larger base can result in an absolute increase that is only slightly smaller. For example, a rate of 2% on 100 units adds 2 units, while 1% on 190 units adds 1.9 units. Thus, the larger population base is the most appropriate explanation, so option A is correct.

Population can continue to grow even after fertility becomes low because population structure changes slowly. If earlier generations contained many children, that large young population will later enter the reproductive ages. Even if each person has fewer children, the total number of potential parents can remain high enough for births to exceed deaths for some time.

This continuing effect is called demographic momentum. It is caused by the previously large youthful population, not by a zero death rate, guaranteed positive migration, or an expanding land area. A country may therefore experience population growth for decades after fertility falls below replacement level. Hence option A is correct. The other choices either make an absolute claim or do not explain the age structure that produces continued growth.

Total population growth combines natural change and net migration. Natural change is found by subtracting the death rate from the birth rate. A negative result means deaths exceed births, while a positive migration rate can offset that loss. Thus, the calculation must include all three components rather than using the birth rate alone.

Natural change is \(13-22=-9\) per thousand. Adding net migration gives \(-9+12=+3\) per thousand. Therefore, the total population still increases by 3 persons per thousand, so option C is correct. Option B represents only natural change and ignores migration.

Population change can be separated into natural increase and net migration. Natural increase is the difference between births and deaths, while net migration is the difference between immigrants and emigrants. Their rates combine to produce the total growth rate, so the relationship is \(\text{total growth} = \text{natural increase} + \text{net migration}\). Rearranging gives \(\text{net migration} = \text{total growth} - \text{natural increase}\).

Substituting the given values gives \(5-15=-10\) per thousand. The negative sign means that more people left than entered, by 10 people per thousand of population during the relevant period. This outflow partly offset the positive natural increase of 15 per thousand and left total growth at 5 per thousand. Therefore, option B, \(-10\) per thousand, is correct.

Percentage growth must be calculated relative to the original population, not the final population. The population rises from 12 million to 14.7 million, so the absolute increase is 14.7 minus 12, which equals 2.7 million. This increase is then compared with the starting value of 12 million.

Using the percentage formula, growth is \(\frac{2.7}{12}\times100=22.5\%\). Equivalently, the final population is 122.5 percent of the original, so the increase is 22.5 percent. Thus option C is correct. A value such as 20 percent would underestimate the increase because it does not represent the actual difference between the two populations relative to the starting population.