The correct answer is option D. "If health care professionals don't look at the "how" and "why" involved in keeping populations healthy, the health of whole communities might be in jeopardy".
Explanation:
Epidemiological studies are important for health care delivery system because they provide information about how diseases spread in populations of humans and, in some cases, animals. By analyzing these studies health care professionals know "how" and "why" diseases spread, and only by knowing it they can advice people. For instance, epidemiological studies allowed people to known that dengue is spread by mosquitoes and health care professionals advice people to keep mosquitoes population at low by protecting themselves and their houses.
