Select the correct answer.
the graph gives the world population between 1950 and 2050. the numbers from today through 2050 are estimates. assume that the projections on the
dotted (upper) line are true. what might be one result of the population change?
estimated world population, 1950-2000, and projections: 2000-2050
16
10.6
10
population (billions)
low
medium
high
3-25
2-
1950
1960
1970
1980
1990
2009
2010
2020
2030
2040
2050
a.
drinking water will be readily available.
b.
basic needs, such as food and water, will be scarce.
c.
food insecurity will decrease.
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1) gene flow

- it is described as the transfer of genes from one population to another population so that frequency of gene is increased.

-a zebra migrates to join a different herd of zebras.

2) natural selection

- a mechanism of evolutionary change in which individuals with advantageous traits survive and reproduce whereas the others ( those that can not adapt) eliminate from the population.

-competition for sunlight leads to taller trees.

3) mutation

- permanent change in the nucleotide sequence of dna ( genetic material) that could have harmful or useful consequences.

-the dna of a snake changes to make its venom stronger.

4) genetic drift - it is a random phenomenon ( that occurs by chance such as fire) that results in change in the gene frequency in a small population.    

-a grassfire randomly sweeps through a population of buffalo and kills most of the animals.

explanation: