Answer:
in-group; out-group
Explanation:
The question states that he is part of the cross-country ski club, and put simply, he is in that group, and hence the answer is in-group. An in-group is defined as "a group of people with a shared interest or identity" and in this case, even though the two clubs both share the interest of skiing, they do not identify as one identity, and thus the group that he is not part of (the downhill ski club) is classified as the out-group.
