Answer:
What motivates White Fang "to obey the strong and to oppress the weak" is the feeling of superiority. the excerpt says "This was no soil for kindliness and affection to blossom in." which shows that White Fang felt as though he was forced to be stronger than "the dog younger or smaller than himself" because showing weakness or affection gives way to vulnerability, as it says to obey the strong and oppress the weak.
Step-by-step explanation:
This is all i could gather from the excerpt, hope it helps at all