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a) Explain "birth rate" in a population ...

a) Explain "birth rate" in a population by taking a suitable example.
b) Write the other two characteristics which only a population shows but an individual cannot.

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a) Birth rate is expressed as the number of births to existing individuals of a populations in given period of time. Eg. If in a pond of 20 lotus 5 new lotus plants are added taking the population by 25, the birth rate is `5/20=0.25`
b) i) Sex ratio: An individual is either a male or a female but a population has sex ratio. Eg: 60 percent of the population are males and 40 percent are females.
ii)Age Pyramid: A population at a given time is composed of individuals of different age groups. If the age distribution is plotted for the populations, the resulting structure is called age pyramid.
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XII BOARDS PREVIOUS YEAR-XII BOARDS-Section C
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