True or False.

17. An employer cannot communicate with its employees who are attempting to unionize about the reasons a union would be harmful. 18. Upon recognition of a union as the employees' bargaining agent, the union and the employer have a duty to bargain in good faith. 19. An employee may fired for participating in "concerted activity". 20. Only an employer may commit "unfair labor practices"; there are no such prohibited activities for a union or its members