Which disease originally caused epidemiological tools to be used for studying chronic diseases?

stroke
diabetes
lung cancer
heart disease

Mario was conducting research regarding the treatment of aids victims using stem cells. he found a source that was written recently and the author was known. unfortunately, he could not determine if it had been peer reviewed.

Andra has a family history of osteoporosis. her doctor advises her to eat foods rich in calcium. which foods should she add to her diet? a. fruits, especially grapes and berries b. unsaturated fats like olive and soybean oil c. beet greens, broccoli, and cheese

The statement defines the use of ethics.