Which of the following statements is true?
a. john is bitten by a tick and contracts lyme disease. john is a vector.
b. anemia and osteoporosis can be prevented by eating foods rich in iron and calcium.
c. trying drugs a few times is okay because it is easy to stop using them.
d. the leading causes of disability in the united states is communicable diseases.

Life expectancy in the united states is (76.4 for men and 81.1 for women). life expectancy is not the same as healthy life expectancy. healthy life expectancy is the number of years a person is expected to live in this number is obtained by subtracting years spent in poor health from overall life expectancy. the world health organization (who) calculates healthy life expectancy in 194 countries. the united states ranks twenty-ninth in the world using this measurement, with an average of of healthy life expectancy. singapore ranks number one (76 years), and japan is number two (75 years).