An employee who has not lodged any complaint of her own is identified as a witness in an employer's internal investigation of a coworker's sexual harassment allegations. The employee is interviewed by the employer and provides corroborating information about sexual harassment she witnessed and/or experienced. Even though this employee has not lodged an internal complaint of her own, has the employee engaged in "protected activity" for which the employer should not retaliate against her? Explain your answer. How should the employer caution to not retaliate against this employee