Is an UIApplication object, UIWindow object, UIView object or any UIView subclass an "Responder object"?

Question

Am I right with my understanding, that an UIApplication object, UIWindow object, UIView object or any UIView subclass is an "Responder object"?

Here they say:

Responder objects in an application include instances of UIApplication, UIWindow, UIView, and all UIView subclasses.

My english is not so well to understand what they mean by the "include". So they may "include" an Responder object, or the big group of famous Responder objects "includes" these classes (or in other words: They belong to this group, called "Responder objects"). Any idea what this means really?

Answer 1

What they mean is they inherit from the UIResponder class.

Answer 2

Yes, they all inherit from UIResponder. You can check this by looking at the API.

Here's the UIApplication API page as an example.