Final answer:
Chris used artifacts, a form of nonverbal communication, to personalize the new apartment by displaying personal objects, pictures, and souvenirs.
Step-by-step explanation:
Chris has personalized the new apartment by hanging pictures, putting out souvenirs, and arranging favorite objects on bookshelves. In the context of nonverbal communication, Chris has relied on artifacts to express personal identity and decorate the living space. Artifacts refer to personal possessions used to communicate identity, tastes, and values, which are not necessarily spoken but can give others insight into one's personality and preferences.