Some are required by the UEFI BIOS - others are boot partitions for the operating system and the recovery media - and the others are your data partition and the actual recovery image itself.
They're ALL required for the system to function normally. If you decide to make ANY alterations, make the set of recovery media (or flash drive) first. Once you alter the partition scheme in any way, the Dell backup and recovery partition will no longer be useable.
Somehow I have managed to damage a partition on my XPS 8700. The recovery media is not able to repair the damaged partition, which means I am not able to reinstall the OS. How do I find out what is missing and repair that so I can reinstall the recovery media?