Active powers - you use the power without a skill (super running).
Active powers - you use a skill with (inate attack(breath))
passive powers - its always on (damage resistance)
Some powers have skills attached to them, flight for one. Being able to fly is great, you can simply roll dex to make simple maneuvers, nothing else is needed. You get the flight skill and your much better at flying. Then you can get the skill Aerobatics to make it look effortless.