During the past 30 years, death rate from heart disease in the United States has declined. At the same time,

A) medical care expenses have increased.
B) rates of smoking tobacco have increased.
C) Americans' life expectancy has decreased.
D) biomedical model acceptance has increased.

The fact that death rates from heart disease have declined suggests that medical interventions and treatments for heart disease have improved. However, this improvement in medical care comes at a financial cost, which is reflected in the increase in medical care expenses. Therefore, option A is the best choice. Option B is incorrect because rates of smoking have actually decreased in the United States over the past 30 years. Option C is also incorrect because Americans' life expectancy has actually increased during this time period. Option D is also incorrect because the biomedical model has been in use for several decades and its acceptance would not have a direct impact on changes in heart disease mortality rates.