Demography is the scientific and statical study ofpopulation, populationchange, size, its components,process and other various related factors is calleddemography.

'John Graunt' is known as the father of demography.

Any two social consequences of rapid population growthrate are:
- Unemployment increases leading to poverty.
- Health, education, transportation and other facilitiesbecomes insufficientin the society.

Sex ratio is the ratio of male population to femalepopulation that is expressed as the number of malepopulation forevery100 female population.

Mid year population is considered as the total population of any place at the mid of the year and calculated asthe average of total population in the first and finalday of the year.

Any two adverse Impact of uncontrolled migration onsocial aspects are:
- Uneven distribution of human resource.
- Centralization of social and infrastructural facilities.

Any two examples of direct measures of populationcontrol measures are:
- Appropriateage at marriage.
-Use of contraceptive devices.

Any two disadvantages of Norplant are:
- Irregular mensurationin the beginning.
- No prevention of STDs, STIs and HIV/AIDS.

Total fertility rate is the average number of live birthsto a women throughout her reproductive period.It summarizes the pattern of age specific fertility rate.It just a mathematical estimation of fertility raterather than actual calculation. TFR can be calculatedby multiplying the sum total of age specificfertilityrate by 5 and dividing by 1,000.

Mathematically,
TFR = 5 * ( ΣASFR/1000 )
Here,
TFR: Total Fertility Rate.
ΣASFR: Total sum of Age Specific Fertility Rate.

A substance or a combination of substances, usuallysteroids administered orally which prevents conceptionor pregnancy is called oral pills.
Its advantagesare:
-It is inexpensive.
-It helps to continue mensuration.
Its disadvantages are:
-It is not effective if not taken regularly.
-Doctor's advice should be taken before using it.

Migration is the movement of people from one placeto another place by crossing its migration defining areaand minimum dime duration by changing usual placeof residence in the searchof betterment and advancement.
Gross migration rate calculated by taking sum oftotal number of in-migrants and out-migrantsin aspecific year per 1,000 mid a yearpopulation of sameyear.

Mathematically
GMR = ( I+O/P ) * 1000
Where,
I= in-migrants.
O= out-migrants.
P= mid-year population.
GMR= GrossMigrantsRate.

Cervical mucus method of contraception refers to testof mucus secreted by cervix to determine the safe &unsafe period of conception. The period with the chanceof conception by checking the cervical mucus carefully.If the mucus is thick and sexual intercourse is done,there is high chance of conception by if the mucus isthin, there less chance of conception. Thus, thisis the brief description about cervical mucus test methodof contraception.

The impact of migration on socio-economic andenvironmental aspects are:

- Socio-economic aspects.
Migration has both positive and negativeimpactson socio-economic aspects. Due to migration, power,facilities, and services get centralized. And suchcentralization results in overcrowdin all fields suchas health, education, employment, security, etc.Consequently, there col be lack of insufficienteducation and a health facilities, unemployment, moretheftand robbery, etc.

- Environmental aspects.
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a. Fecundity and Fertility.

b. Natural and Artificial factor of population change.

It is one of the natural contraception method. It isprobably the 1st scientific method based on periodicabstinenceto be developed. Essentially, a women shouldrecord body temperature immediately on walking eachmorning to get a reading of basal temperature.To get properrecord of every chance of body temperature, thethermometer should be kept either in mouth or armpit.

Rate of natural increase is the rate at which apopulation of a particularplace is increasing ordecreasing in a given year due to the surplus or deficitof births over deaths, expressed as percentage of thebaseyear.

Mathematically,
RNI = (CRR - CDR/1000) * 100
Where,
RNI : Rate of Natural Increase.
CBR: Crude Birth Rate.
COR: Crude Death Rate.

Depo-Provera is a female contraceptive device. It isalso called Depot-medroxyprogesteroneacetate (DMPA).Depo and Megestron. It contains progestin hormonewhich suppressesthe development of ova.
Its advantagesare:
-It's 99% effective.
-No tension of taking pills daily.
Its disadvantages are:
-It may increase the weight of the body in some females.
-It doesn't prevent STDs, STIs and HIV/AIDS.

Population growth rate is the rate at which populationis increasing due to natural increase and net migration,expressed as the percentage of base population.
Rapid population growth rate is the populationgrowth rate with more than 2% and TFR is morethan replacement level (2.1).

Dependency ratio is the ratio of dependent populationto independent population multiplied by 100.

Old and young dependencyratio is calculated by:
CDR = [Pⁿ(0-14) / Pⁿ(15-59)] * 100
ODR = [Pⁿ (60 above) /Pⁿ(15-59)] * 100
Advantages of having knowledge of dependency ratio are:
-To find the total dependent people.
-To find the total independent people.
-To know how many people are dependedtoeach independent people.
-To make policy makers easytoformulate policiesfor dependent and...