5) One night, Tammy is stressed out about her test in her section of the lab and asks Sammy, her twin sister, to take her position to perform it. Sammy is reluctant, but Tammy seems to have a good argument: who’ll know? It won’t hurt anyone. Plus, it will be just this one time.
As much as Sammy looks like Tammy, they are not the same person. By performing the lab for Tammy, Sammy and her sister will both be sanctioned for falsification. As an alternative, Tammy can ask Sammy for help. For example, helping her review the night before may relieve her of the stress she is going through. Sammy should definitely not take the test in place of her sister.