George Perkins Marsh is one of the most well-regarded geographers and environmentalists of the nineteenth century. In his seminal work Man and Nature (1864), Perkins argued that mankind has a destructive influence on the condition of the environment. His ideas were initially on the fringe of accepted geographic theory, but over the years Marsh has come to be revered as a visionary.

HIV/AIDS rates in Sub-Saharan Africa have reached more than 25% in some countries, severely decreasing the populations of these areas. While all of these factors decrease popuations, none are nearly as threatening as the prevalence and expansion of HIV/AIDS.

The global annual natural increase rate is approximately 88,000,000 people per year. The answer choice '1.2 percent' yields an answer of approximately 88,000,000.

The answer choice '12 percent' is a poor choice because it yields an answer of 888,000,000, which is approximately 10 times greater than the actual natural increase rate.  

The answer choice '0.12 percent' is also a poor choice because it yields and answer of 8,800,000, which is nearly 10 times less than the actual natural increase rate.

The answer choices '12 million' and '120 million' are not the best answer choices available because they are not closest to 88 million.

The dependency ratio would increase. The dependency ratio is the ratio of economically-dependent people in a society (those younger than 16 years old or over 65 years old) to the people they depend on (people who are economically productive individuals from 16-65 years old). As the "Baby Boomers" retire, they will rely upon younger generations.

The fertility rate would not increase as the population ages, because the aging "Baby Boomer" generation will not be having more children. Similarly, the rate of natural increase will not increase because the aging of the "Baby Boomers" should not increase the birth rate or decrease the death rate. The childhood mortality rate will not be affected by the aging "Baby Boomers" because the aging of this generation does not directly affect the health of young children. The independency ratio is not a real term used by geographers.

Great Britain had many colonies, including India, United States, and Canada. Since Great Britain had so many colonies, the nation was known as "the empire on which the sun never sets." Mexico did not become one of these colonies.

Since Australia's colonization by the British government in the eighteenth century, the vast majority of Australia's population has lived along the coastlines. The interior of Australia, known as the Outback, is largely barren land with few natural resources or advantages. The natural harbors and resource-rich locations were first settled by European colonists and are still the home of Australia's significant population centers.

Fertility rates rise and fall for a variety of reasons and differ greatly for a variety of reasons. Western Europe has for the last few decades had the lowest fertility rates in the world, which could have a variety of causes, including secularization, which made the religious encouragement for larger families less important.

The global life expectancy is currently in the low 60s, around 63 or 64. Of course, the life expectancy in the developed world is usually in the high 70s and in the developing world it can be closer to 50 or even 40, and this imbalance is one of the great social ills of our times; however, it is worth remembering that in the last one hundred years, life expectancy has soared around the world. In the early twentieth century, the global life expectancy was between 40 and 45.

In Western Europe and North America, the population is basically steady; it is neither climbing nor shrinking dramatically. In Eastern Europe, the population is shrinking. In parts of East Asia, the population is climbing slowly. In Sub-Saharan Africa (as well as South Asia), the population is skyrocketing.

In 2014, Qatar experienced the fastest population growth in the world. The population of Qatar increases by as much as ten percent every year. Qatar is a very small country in the Middle East that has recently undergone a revolutionary growth in economic prosperity. Much of Qatar’s rampant population growth is being driven by immigrants arriving from South Asia in search of work.