Difference between birth rate and death rate per thousand population in a year is called as natural growth rate.

8.74 person per thousand.

Monaco is the most densely populated country of the world.

1.68 crore persons.

1. Human being are producers and consumers of earth's resources.
2. Therefore, it is important to know how many people are there in a country, where do they live, how and why their numbers are increasing and what are their characteristics.

It can be of two types:
(i) Internal
(ii) International
Factors Responsible for internal migration in India:
In India mostly migration are from rural to urben areas. Two factors affect this migration
(i) Push factor
(ii) Pull factor

The elements/factors responsible for population growth or change in size of population are as follows
(i) High birth rate and low death rate In India, after independence there was high birth and high death rate. However, the death rate has declined now considerably but the birth rate continues to remain high.
(ii) Child marriage Early marriages are common in many parts of India due to which more percentage of girls are married in the age group of 15-20 years. This results in giving birth to more number of children.
(iii) Illiteracy Still a large population of India is illiterate. Illiterate persons fail to understand the importance of family planning or the advantage of having a small family.

Five significant characteristics of the adolescent population of India are as follows
(i) Adolescent population constitutes one-fifth of the total population of India.
(ii) They are generally grouped in the age group of 10 to 19 years.
(iii) They are the most important resource for the future.
(iv) Nutritional requirements of adolescents are higher than those of normal child or adult.
(v) In India, a large number of adolescent girls suffer from anaemia.
(vi) The adolescent girls have to be sensitised to the problems they confront.

Migration
Migration is the temporary or permanent relocation of population inside or outside the boundaries of a country or state. 
Types of Migration
1. The two types of migration are internal (within the country from one area to another) and international (between countries).
2. Internal migration does not change the size of the population, but influences the distribution of population within the nation.
Trends of Migration in India
1. The trends of temporary migration in India are of the herders, who take their flocks to different pastures during the summer and winter. 2. These herders live mostly in the hilly and desert areas. Permanent migration occurs from the rural areas to the urban areas in search of employment opportunities as there is great poverty and unemployment in rural areas of India.

Population plays a pivotal role in the present world.
1. It is one of the most important element of the world (universe).
2. It is the point of reference from which all other elements are observed and from which they derive significance and meaning.
Resources, calamities and disasters are all meaning only in relation to human .
1. Coal is a piece of rock and petroleum is a liquid.
2. These are useless until people don't know their utilisation.
3. With the knowledge of utilisation, a nature  think becomes a resources .
4. Natural events like a river flood, earthquake etc. become disaster only when they destroy a crwded village or a town.