Explain the differences between Activity and Fragment components in Android development.

Activity and Fragment are key components in Android, but they serve different roles:

• Activity is a separate screen of the application, representing a point of interaction with the user. Each Activity manages its own lifecycle and displays UI.

• Fragment is a part of the interface within an Activity. Fragments allow breaking down the UI into independent modules that can be reused and combined in different Activities.

Main differences:

1. Lifecycle: Activity has its own lifecycle, while Fragment depends on the lifecycle of the Activity it is in.

2. UI management: Activity is responsible for the entire screen, Fragment for a part of the screen.

3. Reusability: Fragments are convenient for creating adaptive interfaces, for example, showing multiple fragments on one screen on tablets.

4. Interaction: Fragments can interact with each other through the Activity.

Example: in a mail application, an Activity may contain a fragment with a list of emails and a fragment for viewing an email, which are shown sequentially on a phone, and simultaneously on a tablet.