Population Growth

Answer: A. Birth rate is important, but it is only one indicator. Natural increase depends on both births and deaths, not births alone. Total population change also includes migration: people entering add to the population, while people leaving subtract from it. The base population is needed to interpret a percentage rate, because the same rate can represent different numbers in different-sized populations. The time period is also essential because a rate over one year is not the same as a change over several years. A is correct because it includes all these necessary considerations. B is wrong because birth rate clearly relates to population change. C is wrong because area alone does not determine growth. D is wrong because migration may be positive, negative or zero. Memory cue: never interpret one indicator without its context.

Answer: B, total population may decline. Natural increase is positive when births exceed deaths. However, total population change is not determined by natural increase alone; it also includes net migration. Net migration is positive when arrivals exceed departures and negative when departures exceed arrivals. If the negative migration amount is larger than the positive natural increase, the combined total becomes negative. For example, a natural increase of 500 and net migration of −800 gives a total change of −300, so the population declines. A is wrong because positive natural increase can be outweighed by large out-migration. B is correct because it recognises this possibility. C is meaningless because population and area are different quantities. D is wrong because migration directly changes the number of residents. Memory cue: add signed components, not just positive ones.

Answer: A, an increase of 800. Solve in two clear stages. First find natural increase: births − deaths = 2,500 − 1,200 = 1,300. Next find net migration: in-migration − out-migration = 400 − 900 = −500. The minus sign means that 500 more people left than entered. Now add the two signed results: 1,300 + (−500) = 800. Therefore, the total population increases by 800. A is correct. B gives only the natural increase and ignores migration. C incorrectly adds all births and arrivals without subtracting deaths and departures. D gives the size of the net migration loss but ignores the larger natural increase, so it is not the total change. Memory cue: total change = (births − deaths) + (in-migration − out-migration).

Answer: A. A growth rate is a percentage, while absolute increase is the actual number added. To calculate the numerical increase, multiply the rate by the base population. Suppose Area 1 has 10,000 people and Area 2 has 50,000 people, and both grow by 5%. Area 1 adds 500 people, while Area 2 adds 2,500 people. The percentage rate is identical, but the absolute increases differ because the starting populations differ. A is correct. B is wrong because the time period is necessary for interpreting a rate and comparing changes. C is wrong because equal birth rates are not guaranteed and birth rate alone does not define total growth. D is wrong because migration can affect actual population change. Memory cue: percentage compares relative change; absolute increase counts people.

Answer: B, 25 percent. First find the absolute increase: final population − initial population = 100 lakh − 80 lakh = 20 lakh. Percentage growth is calculated using the initial population as the denominator: percentage growth = (increase ÷ initial population) × 100. Therefore, (20 ÷ 80) × 100 = 0.25 × 100 = 25%. B is correct. A would result from treating 20 lakh as 20% without comparing it with the base. C incorrectly uses a different denominator or calculation. D uses the initial figure itself as a percentage and is not a growth calculation. The unit lakh cancels because both quantities use the same unit. Memory cue: percentage growth always uses increase divided by the original population, not the final population.

Answer: A. A declining growth rate does not necessarily mean a declining population. It may mean that the population is still increasing, but at a slower speed. For example, a population growing at 3% and then at 1% is still growing in the second period because 1% is positive; it is simply adding people more slowly than before. A is correct because it separates the direction of change from its speed. B is wrong because a negative rate generally indicates population decline, all else being interpreted consistently. C is wrong because zero births and zero in-migration do not ensure growth, and deaths or out-migration may reduce the population. D is wrong because deaths greatly exceeding births tend to produce negative natural increase. Memory cue: positive but smaller means slower growth, not automatic decline.

The correct answer is A because a sound analysis moves from basic evidence to causes, rates and consequences. First identify the earlier and current population so that the numerical change can be found. Next examine the natural component, births minus deaths, and the migration component, immigration minus emigration. Together these explain the total change. Then calculate or interpret the growth rate, because an absolute increase and a high rate are not identical. Finally consider the effects on housing, employment, education, health services and other planning needs. Option B is incomplete because births alone ignore deaths and migration. Option C gives physical area but not demographic change. Option D measures people per unit area and cannot by itself explain why population changed. Memory cue: compare, decompose, calculate, then plan.

The correct answer is B: examine net migration and age structure together with the birth rate. Population growth is not decided by fertility alone. A falling birth rate tends to reduce natural increase, but high immigration adds people directly and may add many working-age adults. Therefore the total population may still grow, and its age composition may become different from that suggested by births alone. Net migration means immigration minus emigration. Option A is wrong because it ignores this important positive component. Option B is correct because it combines the main demographic evidence needed for a balanced conclusion. Option C confuses two different measures; deaths and births are not interchangeable. Option D is wrong because area helps calculate density but does not by itself explain population growth. Memory cue: falling births do not automatically mean falling total population when migration is large.