These defenses are Reactions.

Block (Melee): Coordination & Size
Dive-for-cover (AoE or Bombard): Sensors & Speed
Dodge (Ranged): Size- & Speed
Evade (Melee): Coordination & Size-
Avoid Maneuver: Varies.

Critical Success: Avoid the attack and choose: a +2 bonus to a related future action, or an immediate counter attack.
Success: Avoid the attack.
Failure: Struck by the attack.
Critical Failure: Struck by the attack and a -2 penalty to Resist Damage or Resist Maneuver.