Exclusive Choice Gateway 
An exclusive choice gateway within a rule flow has at least two named branches, one of these being a default one. Each named branch has a condition associated with it. If all the conditions in gateway are not satisfied, then the default condition will be valid and that condition will not be evaluated.
An exclusive choice gateway can optionally have actions and local definitions as in rule scripts so as to assist complex computations if required. It is not a reusable entity in flow ruleset.
Example
If the percentage scored by the student is greater than equals 35, set grade else set grade = Fail
In the above example you can capture the condition : If the percentage scored by the student is greater than equals 35 in an exclusive choice gateway and execute it in a rule flow.