Final answer:
Tomas is likely in the exploration stage of ethnic identity development, distancing himself from his Filipino heritage and aligning with a Mexican peer group as he seeks independence and attempts to fit in with his chosen friends.
Step-by-step explanation:
Tomas, a 17-year-old Filipino-American male, appears to be in a stage of ethnic identity development where he is exploring his identity by aligning with a peer group that is different from his familial ethnic group. His behavior, such as befriending a clique of Mexican boys and emulating their style, and his refusal to participate in his family's cultural and religious practices, suggests that he is in a stage of searching or experimenting with different aspects of identity, which is typical for adolescents as they develop a sense of independence and individuality. This is part of the normal process of identity formation where students may adopt different behaviors to fit in with their peers, seeking acceptance and a social identity within their chosen group.