Your fellow employee is really upset with the supervisor. She sent an email message to your entire project team of five people from her personal computer complaining about low wages, forced overtime, and lack of understanding about work-life balance. She recommends that the team contact a union organizer. One of the team members posted the email to Facebook. A company executive saw it and demands that the post be removed. The union claims it is a “protected activity.” What elements are necessary for the email to be considered a concerted activity?