The correct answer is: A. predictable and unpredictable.
Uncertain events are events that are not certain to happen. They can be classified into two types: predictable and unpredictable. Predictable events are events that can be predicted with some degree of certainty, such as the weather or the outcome of a sporting event. Unpredictable events are events that cannot be predicted with any degree of certainty, such as natural disasters or terrorist attacks.
Option B is incorrect because possible events are events that can happen, while impossible events are events that cannot happen. Uncertain events can be either possible or impossible.
Option C is incorrect because natural events are events that occur in nature, while artificial events are events that are caused by humans. Uncertain events can be either natural or artificial.
Option D is incorrect because rare events are events that occur infrequently, while continuous events are events that occur continuously. Uncertain events can be either rare or continuous.