Question

question 4 of 10
which factor has added to the average life expectancy?
a. clean water supplies
b. improved vaccinations
c. greater availability of health care
d. all of the above

Explanation:

• Clean water supplies reduce water - borne diseases.
• Improved vaccinations prevent many infectious diseases.
• Greater availability of health care allows for better treatment of illnesses.

Answer:

D. All of the above