Those who persist in the endeavor at long last triumph ...... the odds of life.

Those who persist in the endeavor at long last triumph over the odds of life.
In this context, "over" is used to indicate overcoming or prevailing against challenges or obstacles. The phrase "triumph over" means to achieve victory or success despite facing difficulties. Therefore, "over" is the correct choice to complete the sentence, accurately conveying the idea of overcoming the odds of life through persistence and determination.