Both of these words are used to describe infectious diseases. However, they have very different meanings. A disease that is “endemic” is commonly found within a certain area, but not commonly found outside that area. Whereas a “pandemic” is a disease that is widespread, even global in nature, and threatens all people regardless of where they live. The Spanish Flu of 1918 is one of the most famous recent examples of a “pandemic.” You might remember the recent Ebola crisis was “endemic” to several countries in West Africa, but many feared that the disease would become “pandemic” so people returning from those areas were quarantined and meticulously monitored.

The difficulty of crossing the Mediterranean Sea causes many hundreds of African migrants to perish every year in their attempts to make a new life for themselves in the European Union. Anything that acts as limiting factor or a deterrent to migration is defined as an “intervening obstacle” by geographers and demographers.

Chronic diseases, also referred to as degenerative diseases, are "old age" diseases that involve long-term deterioration. Influenza is an example of an infectious disease in that it is passed by direct transmission, while all of the other answer choices are not directly transmitted. 

The difference between an epidemic and a pandemic is that a pandemic refers to a disease that has spread worldwide, while an epidemic refers to a disease that has only spread regionally. An example of a pandemic is the Spanish influenza virus of 1918 that killed over 40 million people.

Overpopulation, as a defined term, generally occurs when a region has exceeded its “carrying capacity.” The “carrying capacity” of a region refers to number of people a region can reasonably support and sustain. When a region has a greater demand for water and food than it can support it is said to be overpopulated.

The “carrying capacity” of an area refers to the maximum number of people a particular area can sustain (keep alive). If this particular isolated area has enough food to support four thousand people, enough water to support three thousand, and enough shelter to support seven thousand we must consider only the lowest number. If there is only enough water to support three thousand people than this is the “carrying capacity” of the area.

The geographic term “ecumene” refers to the proportion of the Earth’s land that is permanently inhabited by human beings. Over time ecumene has increased slightly. This has been caused by a number of factors, but the two most significant are - overpopulation which causes some people to seek new areas for inhabitation and technological innovation that opens up new parts of the world to human inhabitance.

The idea of “cultural landscapes” is most closely associated with the twentieth century environmental geographer Carl Sauer. Sauer argued that all geographic regions, even those which might appear to be unaffected by mankind’s influence, have been impacted by the growth of the human population. His work was important for spreading the significance of environmental studies in the field of geography.

The Fertile Crescent is a region of land between the Tigris and Euphrates rivers in the Middle East (much of modern day Iraq, Syria, and Jordan). It is often referred to as the “cradle of civilization” because it was in these fertile floodplains that the first agricultural communities and later civilizations began to appear. In the thousands of years since then, however, the region (according to Marsh) has been ruined by overuse by mankind. What was once a fecund floodplain is now mostly an arid desert. Marsh uses the example of the Fertile Crescent to support his theory that mankind negatively impacts the environment, especially as population grows.

The “carrying capacity” of an area refers to the maximum number of people who can be realistically sustained by the geography of that area. This number can be affected by access to food, water, shelter, and other significant factors. The “carrying capacity” can often be quite difficult to compute and is extremely fluid and changeable. This is because most “areas” do not solely sustain themselves (think of how it is common for people in the United States to buy mangoes grown in South Asia), but rather exchange sustaining goods with other “areas.”