What is activity in the Android Foundation activity chapter?

Activity is one of the four components of Android, and it is one of the most commonly used components that can be used to display a view.
The official argument is that the activity is a component of an application that provides a screen to interact with the user in order to do things like making a phone call, sending an email, and looking at a map, as follows:
An Activity was an application component that provides a screens with which users can interact in order to do something, suc h as dial the phone, take a photo, send an email, or view a map.

What is activity in the Android Foundation activity chapter?