By means of natural selection.
I think natural could be the word
Answer: Polyploidy
Explanation:
Polyploidy is defined as the phenomenon by which cells, tissues or organisms with three or more complete sets of chromosomes originate. Such cells, tissues or organisms are called polyploids.
If the genomes of a polyploid species come from the same ancestral species, it is said to be autopolyploid or autoploid. And if they come from two different ancestral species, it is said to be allopolyploid or alloploid. <u>Depending on the number of complete chromosome sets that the species has it is called triploid (3X), tetraploid (4X), pentaploid (5X), hexaploid (6X) and so on, where X is the monoploid number, and not to be confused with the haploid number.
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Redundant genetic elements of polyploid organisms can be transformed into single copies by sub-functionalization, neofunctionalization mechanisms or by the appearance of certain mutations.
<u>Two populations are sympatric when they exist in the same area and thus frequently encounter one another. </u>In general, different species cannot interbreed and produce healthy and fertile offspring due to barriers known as reproductive isolation mechanisms. Polyploidy speciation is common in plants but rare in animals. So, animal species are much less tolerant of changes in ploidy. For example, human embryos that are triploid or tetraploid are not viable, cannot survive.
The factor that explains most of the difference in standards of living among countries around the world is PRODUCTIVITY.
One major measure that can be used to determine the standard of living of people in a particular country is the growth rate of the its Gross Domestic Product [GDP] per capita. The growth rate of GDP is a reflection of the labour productivity of that country. Labour productivity refers to the measurement of the amount of goods and services that are produced in a country by one hour of labour. An increase in productivity signifies an increase in the standard of living of the people in the country. Labour productivity differs from one country to another and this result in difference in the standard of living.
