NCERT Solutions for Class 12 Geography Chapter 3 Population Composition

Ans : (i) (a) Selective migration of male working population
(ii) (d) 15 to 59 years
(iii) (a) Latvia 

Ans : (i) Population composition refers to those characteristics of population which are measurable and helps in distinguishing one group of people from other such as age, sex, literacy rate, occupation etc.


(ii) Age structure represents the number of people of different age groups. It is an important indicator of population composition, since a large size of population in the age group of 15- 59 indicates a large working population.


(iii) The ratio between the number of women and men in the population is called the Sex Ratio. In some countries it is calculated by using the formula:
Male population/Female Population x 1000 or the number of males per thousand females. In India, Female population/Male Population x 1000 or the number of females per thousand males. 

Ans : (i)

The division of population into rural and urban is based on the residence.
This division is necessary because rural and urban lifestyles differ from each other in terms of their livelihood and social conditions.
The age-sex-occupational structure, density of population and level of development vary between rural and urban areas.
The criteria for differentiating rural and urban population varies from country to country.
In general terms, rural areas are those where people are engaged in primary activities and urban areas are those where majority of the working population is engaged in non-primary activities.
The rural and urban differences in sex ratio in Canada and West European countries like Finland are just the opposite of those in African and Asian countries like Zimbabwe and Nepal respectively.
In Western countries, males outnumber females in rural areas and females outnumber the males in urban areas. In countries like Nepal, Pakistan and India the case is reverse.
The excess of females in urban areas of U.S.A., Canada and Europe is the result of influx of females from rural areas to avail of the vast job opportunities.
Farming in these developed countries is also highly mechanised and remains largely a male occupation.
By contrast, the sex ratio in Asian urban areas remains male dominated due to the predominance of male migration.
In countries like India, female participation in farming activity in rural area is fairly high. Shortage of housing, high cost of living, insufficient job opportunities and lack of security in cities, discourage women to migrate from rural to urban areas.


(ii) The sex-age structure of a population refers to the number of females and males in different age groups. A population pyramid is used to show the age-sex structure of the population.
The age-sex pyramid of Nigeria is a triangular shaped pyramid with a wide base and is typical of less developed countries. These have larger populations in lower age groups due to high birth rates. Bangladesh and Mexico also have same population pyramid. As the age increases, the number of females goes on decreasing as compared to males.
Australia's age-sex pyramid is bell shaped and tapered towards the top. This shows birth and death rates are almost equal leading to a near constant population.
The Japan pyramid has a narrow base and a tapered top showing low birth and death rates. The population growth in developed countries is usually zero or negative.
Occupational structure: The working population (age group — 15 to 59) take part in various occupations. More females are engaged in the tertiary and quaternary sector than primary and secondary activities. This is because primary and secondary activities require more muscle power.