You can enroll up to five fingerprints on iPad Air (4th generation) using Touch ID. Touch ID is a feature that allows you to securely and conveniently unlock your iPad, authorize purchases and payments, and sign in to many third-party apps. You can add multiple fingerprints (both of your thumbs and forefingers, for example) or register multiple reads of the same finger to provide even more data from a variety of angles.Reference: =Apple - Support - Manuals, Set up Touch ID on iPad;iPad Air: How to set up and use Apple's new Touch ID fingerprint sensor.

Activities is a feature in Console that allows you to view log messages grouped by the activity they are associated with. This helps you focus on specific log messages and allows for a more complete analysis of your Mac. To view activities in Console, you need to click the Activities button in the toolbar (or use the Touch Bar). If the Activities button is dimmed, you need to click Start in the toolbar first. You can then select an activity to see the log messages for that activity, expand or collapse child activities, and view the details of an activity.Reference: =View activities in Console on Mac;Apple Device Support Exam Prep Guide, page 11.

According to the Apple Device Support Reference Materials, one of the basic troubleshooting steps for peripheral devices is to unplug and reconnect the device1. This can force the Mac to reinitialize the connection and reload any device-specific drivers.Other options, such as connecting the peripheral to a USB hub, unplugging other devices on the same bus, or connecting the peripheral to another Mac, may not necessarily reinitialize the connection or reload the drivers, and may introduce other issues or complications.Reference:1:Apple Device Support Reference Materials, Section 2.3.1, 'Basic Troubleshooting Steps'.

Sidecar is a feature that lets you use your iPad as a display that extends or mirrors your Mac desktop. You can use Sidecar to work with different apps on the different screens, use the same app on both screens, or mirror the screens so that they show the same content. You can also use your Apple Pencil to draw, edit, or mark up documents on your iPad while seeing the updates live on your Mac. Sidecar requires macOS 10.15 or later and iPadOS 13 or later on supported models. You can use Sidecar wirelessly or with a USB cable. To use Sidecar, you need to select your iPad from the Display menu in Control Center or the menu bar on your Mac, or from the AirPlay menu on macOS Catalina. You can also use the sidebar and the Touch Bar on your iPad to access common Mac controls and app-specific commands. The other options are not the correct answer, as they have different functions or are not available on macOS and iPadOS.

Universal Control is a feature that lets you use a single keyboard, mouse, or trackpad to control your Mac and iPad, with the iPad showing its own Home Screen and apps rather than the desktop and apps of your Mac. You can also drag and drop content between your devices. Universal Control requires macOS Monterey or later and iPadOS 15 or later on supported models.

Screen Sharing is a feature that lets you remotely view or control another Mac or share your Mac screen with others over the internet. You can use Screen Sharing to help someone with a problem, collaborate on a project, or access your files and apps. Screen Sharing requires macOS 10.14 or later on both Macs, and an Apple ID or a local network connection.

Stage Manager is not a feature on macOS or iPadOS. It is a feature on watchOS 8 or later that lets you control the camera and microphone on your iPhone from your Apple Watch. You can use Stage Manager to take photos, record videos, zoom in and out, adjust the exposure, mute the sound, and switch between the front and back cameras on your iPhone.Reference:

Apple Device Support Exam Prep Guide, page 6

Use an iPad as a second display for a Mac

Use iPad as a second display for your Mac

Sidecar: Turn an iPad Into a Secondary Mac Display

Use Universal Control on your Mac and iPad

Share the screen of another Mac

[Use Stage Manager on your Apple Watch]

Migration Assistant is a tool that allows you to transfer your data, apps, and settings from one Mac to another. To use Migration Assistant with two Macs, you need to have Wi-Fi turned on and the Macs must be near each other. You also need to update the software on both Macs, if possible, and turn off any antivirus, firewall, or VPN software that might interfere with the transfer. You can then launch Migration Assistant on both Macs and follow the onscreen instructions to select the source and destination Macs, choose the content to transfer, and start the migration process.Reference:Transfer to a new Mac with Migration Assistant - Apple Support,How to Use Migration Assistant to Move Files from One Mac to Another