The infant mortality rate is one of the most important statistics for comparing healthcare, development, disease, and nutrition across various regions. The infant mortality rate of a region reflects the number of deaths within the first year per thousand births. So, any individual who dies less than twelve months after he or she was born will be included in the infant mortality rate.

In the late 1960s and early 1970s, marriage and fertility rates dropped as the Baby Boom generation came to an end. The primary reason why the birth rate declined in the United States in this time period was the relative liberation of women in American society. Women gained greater access to higher educational and were given more opportunities in the work place. Additionally, contraception became available and widely used for the first time. As a general rule, where education of women is high and contraception is easily available, fertility rates will be low.

Total fertility rate measures the number of children conceived by the average woman over the course of her lifetime. The total fertility rate of most of the developed world is around, or slightly less than, two, whereas in much of Africa, the total fertility rate is in excess of four. Other than Sub-Saharan Africa, which has the highest total fertility rate, most of the world’s countries with total fertility rate in excess of four can be found in the Middle East, stretching from Jordan in the West to Pakistan in the East.

The child mortality rate is an important piece of demographic information that helps geographers identify and contextualize the relative levels of wealth, public health, nutrition, and other important factors in various regions. The child mortality rate reflects the number of deaths per thousand children in the first five years of those children’s lives. So if the child mortality rate was twenty-seven, this means that for every thousand children born twenty-seven die before their fifth birthday.

Italy, like many Western European countries, is currently experiencing a negative natural increase rate (which means the population is falling). The United States of America continues to experience population growth, although a lot of it is driven by immigration. Brazil and Mongolia, you might infer, have modest levels of natural increase. But, Angola is in Sub-Saharan Africa and represents the most likely correct answer for this question.

Generation X is the name collectively given to people born after the Baby Boom generation between the late 1960s and the early 1980s. Birth rates were lower for Generation X than for the Baby Boom generation, which means the United States will soon have to deal with the consequences of a slightly aging population where fewer people are working to support more retirees.

In a triangular population pyramid, the youngest people in a society make up the highest percentage of that society. It is symptomatic of high birth rates and high death rates, so the best answer choice here is Liberia. South Africa is somewhat more developed than Liberia, so it has a population pyramid closer to a rectangle. The same is true for Moldova and to a greater extent Andorra and the United Kingdom.

Infant mortality rate measures how many babies, per thousand births, die before their first birthday. In many parts of Sub-Saharan Africa, the number is as high as one hundred. In almost all of the developed world, this number is less than ten. In what may seem like an illogical paradox, a high infant mortality rate generally correlates to a high rate of population growth—this is in part because when a culture believes many of its children will die before reaching adulthood (or even childhood), people of that culture tend to have more babies.

Since the population is expected to double over the period of those 35 years, it is most appropriate described as "doubling time." Since we know nothing of the death rate, crude or otherwise, we cannot determine the natural increase rate or even speak of life expectancy. Similarly, as we know nothing of the demographics, we cannot determine the demographic transition rate. 

Crude birth rate (CBR) is the number of live births per year for every 1,000 people alive. When the crude death rate (CDR) is subtracted from the crude birth rate (CBR), you can determine an area's rate of natural increase. A higher CBR indicates population growth in an area, while a higher CDR indicates population decline.