The correct answer to this open question is the following.
Although there are no options attached or further references and context, we can comment on the following.
What three activities demonstrate athletic stance?
The three activities that can demonstrate athletic stance is Football, baseball, and swimming, for instance.
When talking about athletics, the athletic stance is very important because it is the foundation, the basis from which the athlete is going to start his basic movements to practice the sport and can perform the needed requirements to succeed in any competition.
In football, for instance, you need to start practicing your two-point or three-point stance, depending on the position you play because these are the fundamentals of the game From that basic position comes your basic steps to play the game and be successful with your assignments.
Something similar happens in the above-mentioned sports.