Population Growth

Direct answer: Option A. Natural increase is the difference between the birth rate and the death rate. When the death rate falls but the birth rate stays high, births are greater than deaths, so the population experiences rapid natural increase. This condition may continue until the birth rate also falls or another factor changes. Option A is correct because the gap between births and deaths becomes large and positive. Option B is wrong because negative growth occurs when deaths exceed births or when losses, such as out-migration, are greater than additions. Option C is wrong because equal births and deaths would be needed for zero natural increase, not high births with fewer deaths. Option D is wrong because birth and death rates do not determine whether migration ends. Memory cue: high births plus low deaths creates a large positive natural increase.

The direct answer is B: 5 percent. First find the absolute increase: 12,600 − 12,000 = 600. Percentage growth is calculated by dividing the increase by the original population and multiplying by 100: (600 ÷ 12,000) × 100 = 5%. The original population is the base because we are measuring how much the population changed from its starting level. Option A is wrong because it underestimates the calculated ratio. Option B is correct because 600 is one-twentieth of 12,000, and one-twentieth equals 5 percent. Option C is wrong because it does not use the correct original base. Option D is wrong because the increase is only 600, not 1,200. Memory cue: percentage growth = (new value − old value) ÷ old value × 100.

Correct answer: C, net migration. Population change comes from births, deaths, and migration. Natural increase is births minus deaths, so a low birth rate does not suggest that natural increase is the main source here. However, a large inflow of students and workers directly adds people to the city; when inward migration is greater than outward migration, net migration is positive and increases population. Option C is therefore correct. Option A is wrong because it refers to the balance of births and deaths, not the stated inflow. Option B is wrong because the death rate is not a source of population growth; deaths normally reduce population. Option D is wrong because sex ratio describes the balance between males and females and does not itself measure population increase. Memory cue: “in-migration” means people enter, so it raises population through net migration.

Correct answer: D, rapid population growth. Population growth is strongly affected by the difference between births and deaths. If the birth rate remains high while the death rate falls, many more people are added through births than removed through deaths. This creates a large natural increase, and the population may grow rapidly, especially if migration is not large enough to offset it. Option D is correct. Option A is wrong because the birth rate is still high and the death rate has fallen, so the stated conditions do not point to immediate decline. Option B is wrong because stability would require births and deaths to be approximately balanced, or other changes to offset the difference. Option C is wrong because nothing in the question gives information about migration. Memory cue: high births plus falling deaths creates a wide demographic gap, which can produce rapid growth.

The correct answer is A: eighteen lakh. Absolute growth means the actual increase in population, so subtract the previous population from the current population. Both figures are already expressed in lakh, which makes the calculation simple: 98 lakh − 80 lakh = 18 lakh. Option A is correct because it represents the amount added to the population. Option B is only the previous population, not the increase. Option C is the current population, not the change between the two populations. Option D adds the two populations, but population growth is not found by addition. Remember: absolute growth = current population − previous population. Do not confuse the final population with the amount by which it increased.

The direct answer is A: the birth rate may fall and population growth may slow. Education can improve awareness of health, family planning and the economic or social effects of having many children. If families choose to have fewer children, the average family size decreases and the number of births may also decline. With fewer births, natural population growth can become slower, although the exact result also depends on deaths and migration. A is correct because it states a possible, not unavoidable, effect. B is wrong because higher education does not necessarily make the death rate rise. C is wrong because education does not automatically stop immigration; people may still move for work or other reasons. D is wrong because population growth is not automatically infinite. Common confusion: a smaller family size usually affects fertility and birth rates, not migration directly.

The direct answer is B: twenty percent. Growth rate is calculated using the initial or previous population as the base: growth rate = (current population − previous population) ÷ previous population × 100. The increase is 1 crore 80 lakh − 1 crore 50 lakh = 30 lakh. Convert both values to lakh: previous population = 150 lakh and increase = 30 lakh. Therefore, growth rate = (30 ÷ 150) × 100 = 20%. A is wrong because 30 lakh is not 10% of 150 lakh. C is wrong because it treats the increase as 30% merely because the increase is 30 lakh. D is wrong because 30 is not half of 150. The denominator must be the previous population, not the current population. Memory cue: percentage growth always compares the increase with the starting value.

The direct answer is A: the difference between the birth rate and death rate can be small. Natural increase is found by subtracting the death rate from the birth rate. For example, if the birth rate is 30 per thousand and the death rate is 28 per thousand, natural increase is only 2 per thousand. Both rates are high, but most births are offset by deaths, so the resulting growth is low. A is correct because population growth depends on the gap between the two rates, not simply on whether each rate is called high or low. B is wrong because births directly add people and therefore affect growth. C is wrong because deaths remove people and a high death rate normally reduces growth. D is wrong because migration is not always positive and has not been supplied in the question. Memory cue: compare the rates; do not judge growth from the birth rate alone.

The correct answer is A: six per thousand. Natural increase means the change in population produced only by births and deaths; migration is not included. To calculate it, subtract the death rate from the birth rate: 18 births per thousand − 12 deaths per thousand = 6 per thousand. Option A is correct because it represents the balance left after deaths are deducted from births. Option B is only the death rate, so it does not show population increase. Option C is only the birth rate and ignores deaths. Option D adds births and deaths, but deaths reduce population rather than increase it. Memory cue: natural increase = birth rate − death rate. Do not confuse it with actual population growth, which may also include immigration and emigration.

The correct answer is B: fourteen lakh. An absolute increase is the actual number added to the population, not the percentage itself. Convert 20% to 20/100 and multiply it by the previous population: (20/100) × 70 lakh = 0.2 × 70 lakh = 14 lakh. Thus the population would rise by fourteen lakh; the resulting population would be 84 lakh, although only the increase is asked for. Option A is half of the correct value and may come from an incorrect mental calculation. Option C repeats the rate as a number instead of applying it to the base. Option D is the entire previous population, not its 20% increase. Memory cue: absolute increase = growth rate × original population.

The direct answer is A: resource pressure and housing stress. A rapidly growing population increases demand for drinking water, sanitation, homes, transport, schools and health services. When the supply of water and housing does not expand at a similar pace, the gap between demand and available resources becomes larger. This can lead to overcrowding, competition for water, informal or poorly serviced settlements and pressure on public facilities. The exact severity depends on planning and investment, but pressure is the most reasonable immediate effect. Option B is wrong because every population still needs water. Option C reverses the problem: limited resources do not become unlimited automatically. Option D is not a direct consequence; population stability requires changes in births, deaths or migration. Memory cue: rapid growth raises demand; limited supply creates pressure.

The direct answer is B: twenty percent. Growth percentage compares the increase with the previous population, not with the final population. First identify the values: previous population = 120 lakh and increase = 24 lakh. Use the formula: growth percentage = (increase ÷ previous population) × 100. Substitution gives (24 ÷ 120) × 100 = 0.2 × 100 = 20%. The lakh units cancel because both quantities use the same unit. Option A, 10%, is too small and does not represent 24 out of 120. Option B is correct because 24 is one-fifth of 120, and one-fifth equals 20%. Option C confuses the absolute increase, 24 lakh, with a percentage. Option D uses an incorrect ratio. Memory cue: for growth percentage, the earlier population is the denominator.

The direct answer is A: pressure on housing and services. Positive net migration means more people are entering the area than leaving it. These additional residents increase demand for homes, water supply, sanitation, transport, schools, hospitals and employment-related services. If housing and services do not expand, existing facilities must serve more people, which can produce overcrowding, longer waiting times, higher rents and shortages. The exact outcome depends on planning and the capacity already available, but increased pressure is the most direct conclusion. Option B is wrong because positive net migration adds people rather than removing them. Option C does not follow; migration can remain positive even when services are inadequate. Option D is wrong because the physical area does not automatically increase when population rises. Memory cue: positive net migration increases demand; unchanged supply creates pressure.

The direct answer is C: fifty percent. Growth percentage is calculated by comparing the increase with the previous population. First find the absolute increase: current population − previous population = 24 lakh − 16 lakh = 8 lakh. Then apply the formula: growth percentage = (increase ÷ previous population) × 100. Thus, (8 ÷ 16) × 100 = 0.5 × 100 = 50%. The lakh units cancel because both populations use the same unit. Option A, 25%, is incorrect because 4 lakh would be 25% of 16 lakh, not the actual increase of 8 lakh. Option B, 40%, does not come from the correct ratio. Option C is correct because 8 lakh is exactly half of 16 lakh. Option D, 60%, is also not the increase as a share of the original population. Common warning: use the previous population as the denominator, not the current population.

The correct answer is A: population growth is a change in the number of people over a period of time. To understand the idea, compare a population at an earlier date with its population at a later date. If the later number is greater, there is growth; if it is smaller, there is decline; if it is equal, there is no numerical change. Births, deaths and migration can produce this change. Option A is correct because it includes both population and time, which are essential parts of the definition. Option B is about a physical feature and does not count people. Option C measures a river, not a population. Option D describes soil and has no direct meaning for population growth. A useful memory cue is: population growth means “people changing in number over time,” not change in any natural object.

The correct answer is B: the initial and final population are necessary for a basic comparison. First find how many people were present at the beginning of the chosen period and how many were present at the end. The numerical change is final population minus initial population. For example, if a place rises from 10 lakh to 12 lakh people, the increase is 2 lakh. A percentage growth rate would additionally require the time period, but the two population totals are still the starting evidence. Option A is about vegetation, not human population. Option B is correct because both figures show the direction and amount of change. Option C only identifies a water feature. Option D describes a visual property of a mountain. Memory cue: to measure change, compare “before” with “after.”

The correct answer is C: population increases when the components adding people are greater than the components removing people. Births and in-migration add to the population. Deaths and out-migration reduce it. In simple form, change = births + in-migration − deaths − out-migration. If this balance is positive, the final population is larger than the initial population. Option A is wrong because low births and low in-migration do not normally create increase; other components must also be considered. Option B describes reducing components and usually pushes population downward. Option C is correct because it states the complete balance principle. Option D is wrong because a place with no people cannot show an increase in its resident population under the situation described. Memory cue: add births and arrivals; subtract deaths and departures.

The correct answer is D: the final population is less than the initial population. Population decline is identified by comparing the total number of people at two times. If final population < initial population, the population has declined during that period. Option A is the opposite: a larger final total indicates increase. Option B shows positive natural change because births exceed deaths, although migration could still alter the final total; it is not by itself the simplest sign of overall decline. Option C means that migration adds more people than it removes, which generally supports growth rather than decline. Option D is correct because it directly compares the two total populations. Possible causes include more deaths, fewer births, out-migration or a combination of these. Memory cue: decline means the “after” number is smaller than the “before” number.

Direct answer: B, positive. Natural increase is calculated as births minus deaths during a given period, without including migration. For example, if 120 babies are born and 80 people die, the natural increase is 120 − 80 = 40, which is above zero. Therefore, the population has a positive natural increase. A is wrong because natural increase becomes negative when deaths are greater than births. B is correct because births are greater here. C is wrong because the result is zero only when births and deaths are equal. D is wrong because the idea is directly related to the difference between births and deaths. Remember: births − deaths; a result above zero means positive natural increase.

Direct answer: A, natural decrease can occur. Natural change is found by comparing births and deaths. If deaths are more numerous than births, the calculation births − deaths gives a negative result. This means the population may decrease naturally, before considering migration. A is correct because it describes this negative natural change. B is wrong: more deaths do not make a population double; they can reduce it. C is wrong because the physical area of a place does not automatically change when its population changes. D is wrong because a higher death rate does not make the birth rate disappear; births may still continue. Migration can later increase or decrease the total population, but it does not change the fact that deaths exceeding births produce natural decrease. Memory cue: more deaths than births means a minus sign.

Direct answer: C. Birth rate tells us how many births occur in relation to the population during a period. When the birth rate rises, more people are added through births. If the death rate is low at the same time, births greatly exceed deaths, so natural increase and overall population growth can become faster. C is correct because it carefully says “can” become faster; the result also depends on deaths and migration. A is wrong because more births do not by themselves guarantee decline. B is wrong because a higher birth rate does not mean that only deaths will be measured. D is wrong because birth rate and migration are separate population processes. Common confusion: never judge growth from the birth rate alone; compare births, deaths, and migration together.

Direct answer: D, improvement in health facilities. Death rate is the number of deaths in relation to the population during a period. Better health facilities can provide timely treatment, vaccination, maternal care, medicines, and emergency support; these improvements can reduce deaths and therefore lower the death rate. D is correct because it has a direct connection with human survival and public health. A is wrong because the colour of forests does not directly determine the number of deaths. B is wrong because the length of a river is not a population-health measure. C is wrong because changing a mountain’s name has no direct demographic effect. The wording says “one reason,” so D need not be the only possible reason. Memory cue: better healthcare generally helps people live longer and lowers mortality.

Direct answer: A. Migration means the movement of people from one place to another. When people enter an area, its population can increase; when people leave, its population can decrease. Thus migration changes population growth even though it does not change the natural increase, which is calculated from births and deaths. A is correct because it includes both directions of movement. B is wrong: migration is a human movement, not a process that changes only rainfall. C is wrong because migration does not form mountains. D is wrong because the physical area of a place does not become zero when people move. In-migration means entering, while out-migration means leaving. Memory cue: people in add to a place; people out subtract from it.

Direct answer: C, people leaving an area. Out-migration is the movement of residents from a particular area to another place. For that original area, these people are counted as leaving, so out-migration can reduce its population if the number leaving is greater than the number entering. C is correct because “out” indicates movement away from the area being studied. A is the opposite process and is called in-migration. B concerns births, which are a natural population process, not migration. D concerns deaths and mortality, also not movement between places. The effect is always considered relative to a specified area: people leaving one area are simultaneously entering another. Memory cue: out = outside or away; in = into the area.

Direct answer: D. Net migration is the difference between the number of people entering an area and the number leaving it. It can be written as in-migration minus out-migration. If 500 people enter and 300 leave, net migration is +200, so it is positive. If more leave than enter, the result is negative. D is correct because it names both movements that determine net migration. A is the basis of natural increase, not net migration. B and C describe physical or economic relationships, not population movement. Net migration should not be confused with total migration, which may count movements without showing the balance. Memory cue: net means the balance left after subtracting out-migration from in-migration.