Scientists are creating vaccinations that prevent people from getting bird flu. If the virus mutates, a new vaccine needs to be made. The vaccine needs to be tested, which can be dangerous. It also takes a long time for scientists to know whether the vaccine works.
A, C, D i believe are the answers...
C. Emotions are feelings that are triggered by thoughts or events because they have reasoning, others are not a factor in its main definition, and emotions do offer some insight to a persons mental health.
