If a developer wants to develop a file background download function, there needs to be a Page Ability to provide UI pages, and a Service Ability to provide the background file download function. Which of the following can invoke Service Ability in Page Ability?

If a user wants to migrate the video of his mobile phone to the smart screen for display on a video call, what are the correct items in the description of the scene?

What are the reasons why a developer wants to use the previewer in DevEco Studio to view the application interface of the design, but the previewer cannot be used?

Regarding the Tabs component and the TabContent component, the following description is correct

When a developer receives a new product demand and asks the user to remake old documents such as paper letters into electronic versions, the application can improve the remake effect of old documents and make the work more correct. What kind of AI-enabled capabilities can be leveraged by HarmonyOSto achieve this?