Final answer:
The Main Activity specifies the first activity to launch when an app is started in Android development.
Step-by-step explanation:
The Main Activity specifies the first activity to launch when an app is started in Android development. It is declared in the AndroidManifest.xml file by using the intent-filter and ACTION_MAIN tags. The Main Activity serves as the entry point for the app and is responsible for initializing the user interface and managing the app's lifecycle.