Final answer:
True, adolescents with multiple physical activity-related identities are likely to perceive high levels of competence. Participation in various activities aids in identity formation and enhances their sense of mastery and confidence.
Step-by-step explanation:
The statement that adolescents with multiple physical activity-related identities are likely to perceive high levels of competence in those activities is true. This concept aligns with psychosocial development theories, which suggest that during adolescence, individuals are in the process of forming their identities, which includes exploring different roles and activities. Participating in various physical activities can help adolescents develop a sense of mastery and self-efficacy, contributing to a stronger sense of competence. Moreover, being involved in multiple activities provides opportunities to establish different social connections and roles, further enhancing their identity formation.