Answer:
The UN projects that the global population increases from a population of 7.7 billion in 2019 to 10.9 billion by the end of the century. By that time, the UN projects, fast global population growth will come to an end.
Beneath the global level, there are of course, big differences between different world regions and countries. While in some regions the world population will likely grow rapidly for the coming decades other regions will continue to see declining population numbers.
Global population growth is determined by the number of births and deaths. Improving health is increasing the size of the population as it is decreasing mortality. The countervailing trend are falling fertility rates – the trend of couples having fewer children is what brought rapid population growth to an end in many countries already, and what will bring an end to rapid population growth globally.
The global population growth rate has already slowed down considerably: It reached its peak at over 2% in the late 1960s and has been falling since.
The UN projections for the global population growth rates, which have been produced since the 1950s, have a good track record in projecting the size of the global population.
While the UN projections are most widely know there are other very carefully produced projections. The demographers of WC-IIASA model what will happen according to different scenarios and make clear that the population growth rate tomorrow depends on what we do today. Rapid progress in getting children and especially girls into schools will result in a much smaller global population.
The biggest disagreement between different projections is concerning the future of Africa. While the UN projects a 3.5-fold increase of the population of Africa, other researchers find a much smaller increase more likely.
Explanation:
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Natural selection can cause microevolution (change in allele frequencies), with fitness-increasing alleles becoming more common in the population.
When exercising is when the lungs work the hardest because you're using a lot of muscles and are running around and are using force in your body so the lung works really hard to make sure the body gets enough air while working out.
The presence of oxygen determines which process cells will use
