UCLA Health conducts a study to determine the full effects of a new vaccine to treat the common flu. They select 50 volunteers to test the vaccine with, which were then randomly divided into two equal groups of 25 individuals each. One group is given the vaccine being tested to treat the common flu, while the other group is not given the vaccine. After a month, two months, four months, six months, and a full year each group is asked to come in to analyze their reaction to the vaccine and its ability to help absolve many symptoms of the common flu. 1. Identify whether the study is an experiment or an observational study. 2. If it's an experiment: State about what the explanatory variable is, and what the response variable is. If it's an observational study: State whether the study is retrospective or prospective