Final answer:
A person born in the US has a life expectancy of approximately 79 years, while someone born in Sierra Leone has a much lower life expectancy of around 50 years. The correct answer is a. 75 years; 50 years.
Step-by-step explanation:
The life expectancy of a person born in the US is roughly 79 years, while someone born in the sub-Saharan nation of Sierra Leone has a life expectancy of approximately 50 years. Therefore, the answer to the student's question is: a. 75 years; 50 years.
Life expectancy can serve as a measure of the overall health of a population. It is affected by a variety of factors, including healthcare access, nutrition, sanitation, and lifestyle. While the United States, a highly developed country, has a life expectancy that is not at the top among developed nations, it is significantly higher than that of many developing countries. Sierra Leone, in sub-Saharan Africa, has one of the lowest life expectancies in the world, which is influenced by factors such as poverty, healthcare infrastructure, and diseases.