A. No. The new AD snapshot functionality introduced in Windows Server 2008 allows a point-in-time copy of AD to be taken and viewed using tools like LDP, ADSIEdit, and AD Users and Computers through a defined LDAP port. However, you can't roll AD back to the content of a snapshot.
The AD snapshots feature is designed to help you decide which backup you want to restore by letting you see the state of the AD at different points in the past, or to allow you to view the state of objects and attributes without having to perform a restore. You can't copy or restore objects from an AD snapshot, you can only export objects and then import them into the live AD.
Consider that before AD snapshots, you would have had to boot a domain controller in directory services restore mode, restore the backup, and hope it's the right one. If not, you'd restore another backup, and so on. With AD snapshots, you can look at the snapshot online, make sure it's the right data, and then boot into directory services restore mode and know the right backup to use.