Some good times to study include right after school, after some exercise, or right before bed (you think about it while you sleep)
Answer:
It is an infection caused by a virus in your body
Explanation:
Epidemiologists are scientists who study diseases within populations of people. In essence, these public health professionals analyze what causes disease outbreaks in order to treat existing diseases and prevent future outbreaks.
Therefore the most precise answer is
D) it states both their analytical work (to study causes and patterns) and also what they pretend to achieve(to contain or treatment) but doesn't fully answer the question "Why their concern is so diverse"
A) Does not only give a full valid definition but answers the question "why they concern is so diverse (extensive)?"
because they study "ALL" diseases..
Thus, the correct answer is A
