The Warrior 1 pose works the arms and legs, strengthens the back and opens the chest. Note the position of the knee which aligns with the middle toe directly over the foot.
In Warrior 2 pose both legs are strengthened in this pose. It can also help the knee muscles strengthen. The shoulders are stretched and the arms are strengthened.
In Warrior 3 pose feel a stretch from the toes of the raised leg to the fingers in front of you.